diff --git a/packages/babel-core/src/config/validation/option-assertions.js b/packages/babel-core/src/config/validation/option-assertions.js
index 7c76f97937..a00f430b8c 100644
--- a/packages/babel-core/src/config/validation/option-assertions.js
+++ b/packages/babel-core/src/config/validation/option-assertions.js
@@ -13,16 +13,54 @@ import type {
   SourceTypeOption,
   CompactOption,
   RootInputSourceMapOption,
+  NestingPath,
 } from "./options";
 
 export type ValidatorSet = {
   [string]: Validator<any>,
 };
 
-export type Validator<T> = (string, mixed) => T;
+export type Validator<T> = (OptionPath, mixed) => T;
+
+export function msg(loc: NestingPath | GeneralPath) {
+  switch (loc.type) {
+    case "root":
+      return ``;
+    case "env":
+      return `${msg(loc.parent)}.env["${loc.name}"]`;
+    case "overrides":
+      return `${msg(loc.parent)}.overrides[${loc.index}]`;
+    case "option":
+      return `${msg(loc.parent)}.${loc.name}`;
+    case "access":
+      return `${msg(loc.parent)}[${JSON.stringify(loc.name)}]`;
+    default:
+      throw new Error(`Assertion failure: Unknown type ${loc.type}`);
+  }
+}
+
+export function access(loc: GeneralPath, name: string | number): AccessPath {
+  return {
+    type: "access",
+    name,
+    parent: loc,
+  };
+}
+
+export type OptionPath = $ReadOnly<{
+  type: "option",
+  name: string,
+  parent: NestingPath,
+}>;
+type AccessPath = $ReadOnly<{
+  type: "access",
+  name: string | number,
+  parent: GeneralPath,
+}>;
+type GeneralPath = OptionPath | AccessPath;
 
 export function assertSourceMaps(
-  key: string,
+  loc: OptionPath,
   value: mixed,
 ): SourceMapsOption | void {
   if (
@@ -32,21 +70,24 @@ export function assertSourceMaps(
     value !== "both"
   ) {
     throw new Error(
-      `.${key} must be a boolean, "inline", "both", or undefined`,
+      `${msg(loc)} must be a boolean, "inline", "both", or undefined`,
     );
   }
   return value;
 }
 
-export function assertCompact(key: string, value: mixed): CompactOption | void {
+export function assertCompact(
+  loc: OptionPath,
+  value: mixed,
+): CompactOption | void {
   if (value !== undefined && typeof value !== "boolean" && value !== "auto") {
-    throw new Error(`.${key} must be a boolean, "auto", or undefined`);
+    throw new Error(`${msg(loc)} must be a boolean, "auto", or undefined`);
   }
   return value;
 }
 
 export function assertSourceType(
-  key: string,
+  loc: OptionPath,
   value: mixed,
 ): SourceTypeOption | void {
   if (
@@ -56,14 +97,14 @@ export function assertSourceType(
     value !== "unambiguous"
   ) {
     throw new Error(
-      `.${key} must be "module", "script", "unambiguous", or undefined`,
+      `${msg(loc)} must be "module", "script", "unambiguous", or undefined`,
     );
   }
   return value;
 }
 
 export function assertInputSourceMap(
-  key: string,
+  loc: OptionPath,
   value: mixed,
 ): RootInputSourceMapOption | void {
   if (
@@ -71,75 +112,82 @@ export function assertInputSourceMap(
     typeof value !== "boolean" &&
     (typeof value !== "object" || !value)
   ) {
-    throw new Error(".inputSourceMap must be a boolean, object, or undefined");
+    throw new Error(`${msg(loc)} must be a boolean, object, or undefined`);
   }
   return value;
 }
 
-export function assertString(key: string, value: mixed): string | void {
+export function assertString(loc: GeneralPath, value: mixed): string | void {
   if (value !== undefined && typeof value !== "string") {
-    throw new Error(`.${key} must be a string, or undefined`);
+    throw new Error(`${msg(loc)} must be a string, or undefined`);
   }
   return value;
 }
 
-export function assertFunction(key: string, value: mixed): Function | void {
+export function assertFunction(
+  loc: GeneralPath,
+  value: mixed,
+): Function | void {
   if (value !== undefined && typeof value !== "function") {
-    throw new Error(`.${key} must be a function, or undefined`);
+    throw new Error(`${msg(loc)} must be a function, or undefined`);
   }
   return value;
 }
 
-export function assertBoolean(key: string, value: mixed): boolean | void {
+export function assertBoolean(loc: GeneralPath, value: mixed): boolean | void {
   if (value !== undefined && typeof value !== "boolean") {
-    throw new Error(`.${key} must be a boolean, or undefined`);
+    throw new Error(`${msg(loc)} must be a boolean, or undefined`);
   }
   return value;
 }
 
-export function assertObject(key: string, value: mixed): {} | void {
+export function assertObject(loc: GeneralPath, value: mixed): {} | void {
   if (
     value !== undefined &&
     (typeof value !== "object" || Array.isArray(value) || !value)
   ) {
-    throw new Error(`.${key} must be an object, or undefined`);
+    throw new Error(`${msg(loc)} must be an object, or undefined`);
   }
   return value;
 }
 
-export function assertArray(key: string, value: mixed): ?$ReadOnlyArray<mixed> {
+export function assertArray(
+  loc: GeneralPath,
+  value: mixed,
+): ?$ReadOnlyArray<mixed> {
   if (value != null && !Array.isArray(value)) {
-    throw new Error(`.${key} must be an array, or undefined`);
+    throw new Error(`${msg(loc)} must be an array, or undefined`);
   }
   return value;
 }
 
-export function assertIgnoreList(key: string, value: mixed): IgnoreList | void {
-  const arr = assertArray(key, value);
+export function assertIgnoreList(
+  loc: OptionPath,
+  value: mixed,
+): IgnoreList | void {
+  const arr = assertArray(loc, value);
   if (arr) {
-    arr.forEach((item, i) => assertIgnoreItem(key, i, item));
+    arr.forEach((item, i) => assertIgnoreItem(access(loc, i), item));
   }
   return (arr: any);
 }
-function assertIgnoreItem(
-  key: string,
-  index: number,
-  value: mixed,
-): IgnoreItem {
+function assertIgnoreItem(loc: GeneralPath, value: mixed): IgnoreItem {
   if (
     typeof value !== "string" &&
     typeof value !== "function" &&
     !(value instanceof RegExp)
   ) {
     throw new Error(
-      `.${key}[${index}] must be an array of string/Funtion/RegExp values, or undefined`,
+      `${msg(
+        loc,
+      )} must be an array of string/Funtion/RegExp values, or undefined`,
     );
   }
   return value;
 }
 
 export function assertConfigApplicableTest(
-  key: string,
+  loc: OptionPath,
   value: mixed,
 ): ConfigApplicableTest | void {
   if (value === undefined) return value;
@@ -147,12 +195,14 @@ export function assertConfigApplicableTest(
   if (Array.isArray(value)) {
     value.forEach((item, i) => {
       if (!checkValidTest(item)) {
-        throw new Error(`.${key}[${i}] must be a string/Function/RegExp.`);
+        throw new Error(
+          `${msg(access(loc, i))} must be a string/Function/RegExp.`,
+        );
       }
     });
   } else if (!checkValidTest(value)) {
     throw new Error(
-      `.${key} must be a string/Function/RegExp, or an array of those`,
+      `${msg(loc)} must be a string/Function/RegExp, or an array of those`,
     );
   }
   return (value: any);
@@ -167,7 +217,7 @@ function checkValidTest(value: mixed): boolean {
 }
 
 export function assertConfigFileSearch(
-  key: string,
+  loc: OptionPath,
   value: mixed,
 ): ConfigFileSearch | void {
   if (
@@ -176,7 +226,7 @@ export function assertConfigFileSearch(
     typeof value !== "string"
   ) {
     throw new Error(
-      `.${key} must be a undefined, a boolean, a string, ` +
+      `${msg(loc)} must be a undefined, a boolean, a string, ` +
         `got ${JSON.stringify(value)}`,
     );
   }
@@ -185,7 +235,7 @@ export function assertConfigFileSearch(
 }
 
 export function assertBabelrcSearch(
-  key: string,
+  loc: OptionPath,
   value: mixed,
 ): BabelrcSearch | void {
   if (value === undefined || typeof value === "boolean") return value;
@@ -193,44 +243,43 @@ export function assertBabelrcSearch(
   if (Array.isArray(value)) {
     value.forEach((item, i) => {
       if (!checkValidTest(item)) {
-        throw new Error(`.${key}[${i}] must be a string/Function/RegExp.`);
+        throw new Error(
+          `${msg(access(loc, i))} must be a string/Function/RegExp.`,
+        );
       }
     });
   } else if (!checkValidTest(value)) {
     throw new Error(
-      `.${key} must be a undefined, a boolean, a string/Function/RegExp ` +
+      `${msg(loc)} must be a undefined, a boolean, a string/Function/RegExp ` +
         `or an array of those, got ${JSON.stringify(value)}`,
     );
   }
   return (value: any);
 }
 
-export function assertPluginList(key: string, value: mixed): PluginList | void {
-  const arr = assertArray(key, value);
+export function assertPluginList(
+  loc: OptionPath,
+  value: mixed,
+): PluginList | void {
+  const arr = assertArray(loc, value);
   if (arr) {
     // Loop instead of using `.map` in order to preserve object identity
     // for plugin array for use during config chain processing.
-    arr.forEach((item, i) => assertPluginItem(key, i, item));
+    arr.forEach((item, i) => assertPluginItem(access(loc, i), item));
   }
   return (arr: any);
 }
-function assertPluginItem(
-  key: string,
-  index: number,
-  value: mixed,
-): PluginItem {
+function assertPluginItem(loc: GeneralPath, value: mixed): PluginItem {
   if (Array.isArray(value)) {
     if (value.length === 0) {
-      throw new Error(`.${key}[${index}] must include an object`);
+      throw new Error(`${msg(loc)} must include an object`);
     }
 
     if (value.length > 3) {
-      throw new Error(
-        `.${key}[${index}] may only be a two-tuple or three-tuple`,
-      );
+      throw new Error(`${msg(loc)} may only be a two-tuple or three-tuple`);
     }
 
-    assertPluginTarget(key, index, true, value[0]);
+    assertPluginTarget(access(loc, 0), value[0]);
 
     if (value.length > 1) {
       const opts = value[1];
@@ -240,38 +289,31 @@ function assertPluginItem(
         (typeof opts !== "object" || Array.isArray(opts))
       ) {
         throw new Error(
-          `.${key}[${index}][1] must be an object, false, or undefined`,
+          `${msg(access(loc, 1))} must be an object, false, or undefined`,
         );
       }
     }
     if (value.length === 3) {
       const name = value[2];
       if (name !== undefined && typeof name !== "string") {
-        throw new Error(`.${key}[${index}][2] must be a string, or undefined`);
+        throw new Error(
+          `${msg(access(loc, 2))} must be a string, or undefined`,
+        );
       }
     }
   } else {
-    assertPluginTarget(key, index, false, value);
+    assertPluginTarget(loc, value);
   }
 
   return (value: any);
 }
-function assertPluginTarget(
-  key: string,
-  index: number,
-  inArray: boolean,
-  value: mixed,
-): PluginTarget {
+function assertPluginTarget(loc: GeneralPath, value: mixed): PluginTarget {
   if (
     (typeof value !== "object" || !value) &&
     typeof value !== "string" &&
     typeof value !== "function"
   ) {
-    throw new Error(
-      `.${key}[${index}]${
-        inArray ? `[0]` : ""
-      } must be a string, object, function`,
-    );
+    throw new Error(`${msg(loc)} must be a string, object, function`);
   }
   return value;
 }
diff --git a/packages/babel-core/src/config/validation/options.js b/packages/babel-core/src/config/validation/options.js
index 5b4585be02..085f0d3608 100644
--- a/packages/babel-core/src/config/validation/options.js
+++ b/packages/babel-core/src/config/validation/options.js
@@ -5,6 +5,8 @@ import Plugin from "../plugin";
 
 import removed from "./removed";
 import {
+  msg,
+  access,
   assertString,
   assertBoolean,
   assertObject,
@@ -21,6 +23,7 @@ import {
   assertSourceType,
   type ValidatorSet,
   type Validator,
+  type OptionPath,
 } from "./option-assertions";
 
 const ROOT_VALIDATORS: ValidatorSet = {
@@ -248,24 +251,62 @@ export type SourceTypeOption = "module" | "script" | "unambiguous";
 export type CompactOption = boolean | "auto";
 export type RootInputSourceMapOption = {} | boolean;
 
-export type OptionsType =
+export type OptionsSource =
   | "arguments"
-  | "env"
-  | "preset"
-  | "override"
   | "configfile"
   | "babelrcfile"
-  | "extendsfile";
+  | "extendsfile"
+  | "preset";
+
+type RootPath = $ReadOnly<{
+  type: "root",
+  source: OptionsSource,
+}>;
+type OverridesPath = $ReadOnly<{
+  type: "overrides",
+  index: number,
+  parent: RootPath,
+}>;
+type EnvPath = $ReadOnly<{
+  type: "env",
+  name: string,
+  parent: RootPath | OverridesPath,
+}>;
+export type NestingPath = RootPath | OverridesPath | EnvPath;
+
+function getSource(loc: NestingPath): OptionsSource {
+  return loc.type === "root" ? loc.source : getSource(loc.parent);
+}
+
+export function validate(type: OptionsSource, opts: {}): ValidatedOptions {
+  return validateNested(
+    {
+      type: "root",
+      source: type,
+    },
+    opts,
+  );
+}
+
+function validateNested(loc: NestingPath, opts: {}) {
+  const type = getSource(loc);
 
-export function validate(type: OptionsType, opts: {}): ValidatedOptions {
   assertNoDuplicateSourcemap(opts);
 
   Object.keys(opts).forEach(key => {
+    const optLoc = {
+      type: "option",
+      name: key,
+      parent: loc,
+    };
+
     if (type === "preset" && NONPRESET_VALIDATORS[key]) {
-      throw new Error(`.${key} is not allowed in preset options`);
+      throw new Error(`${msg(optLoc)} is not allowed in preset options`);
     }
     if (type !== "arguments" && ROOT_VALIDATORS[key]) {
-      throw new Error(`.${key} is only allowed in root programmatic options`);
+      throw new Error(
+        `${msg(optLoc)} is only allowed in root programmatic options`,
+      );
     }
     if (
       type !== "arguments" &&
@@ -274,48 +315,47 @@ export function validate(type: OptionsType, opts: {}): ValidatedOptions {
     ) {
       if (type === "babelrcfile" || type === "extendsfile") {
         throw new Error(
-          `.${key} is not allowed in .babelrc or "extend"ed files, only in root programmatic options, ` +
+          `${msg(
+            optLoc,
+          )} is not allowed in .babelrc or "extends"ed files, only in root programmatic options, ` +
             `or babel.config.js/config file options`,
         );
       }
 
       throw new Error(
-        `.${key} is only allowed in root programmatic options, or babel.config.js/config file options`,
+        `${msg(
+          optLoc,
+        )} is only allowed in root programmatic options, or babel.config.js/config file options`,
       );
     }
-    if (type === "env" && key === "env") {
-      throw new Error(`.${key} is not allowed inside another env block`);
-    }
-    if (type === "env" && key === "overrides") {
-      throw new Error(`.${key} is not allowed inside an env block`);
-    }
-    if (type === "override" && key === "overrides") {
-      throw new Error(`.${key} is not allowed inside an overrides block`);
-    }
 
     const validator =
       COMMON_VALIDATORS[key] ||
       NONPRESET_VALIDATORS[key] ||
       BABELRC_VALIDATORS[key] ||
-      ROOT_VALIDATORS[key];
+      ROOT_VALIDATORS[key] ||
+      throwUnknownError;
 
-    if (validator) validator(key, opts[key]);
-    else throw buildUnknownError(key);
+    validator(optLoc, opts[key]);
   });
 
   return (opts: any);
 }
 
-function buildUnknownError(key: string) {
+function throwUnknownError(loc: OptionPath) {
+  const key = loc.name;
+
   if (removed[key]) {
     const { message, version = 5 } = removed[key];
 
     throw new ReferenceError(
-      `Using removed Babel ${version} option: .${key} - ${message}`,
+      `Using removed Babel ${version} option: ${msg(loc)} - ${message}`,
     );
   } else {
     // eslint-disable-next-line max-len
-    const unknownOptErr = `Unknown option: .${key}. Check out http://babeljs.io/docs/usage/options/ for more information about options.`;
+    const unknownOptErr = `Unknown option: ${msg(
+      loc,
+    )}. Check out http://babeljs.io/docs/usage/options/ for more information about options.`;
 
     throw new ReferenceError(unknownOptErr);
   }
@@ -331,27 +371,53 @@ function assertNoDuplicateSourcemap(opts: {}): void {
   }
 }
 
-function assertEnvSet(key: string, value: mixed): EnvSet<ValidatedOptions> {
-  const obj = assertObject(key, value);
+function assertEnvSet(loc: OptionPath, value: mixed): EnvSet<ValidatedOptions> {
+  if (loc.parent.type === "env") {
+    throw new Error(`${msg(loc)} is not allowed inside of another .env block`);
+  }
+  const parent: RootPath | OverridesPath = loc.parent;
+
+  const obj = assertObject(loc, value);
   if (obj) {
     // Validate but don't copy the .env object in order to preserve
     // object identity for use during config chain processing.
-    for (const key of Object.keys(obj)) {
-      const env = assertObject(key, obj[key]);
-      if (env) validate("env", env);
+    for (const envName of Object.keys(obj)) {
+      const env = assertObject(access(loc, envName), obj[envName]);
+      if (!env) continue;
+
+      const envLoc = {
+        type: "env",
+        name: envName,
+        parent,
+      };
+      validateNested(envLoc, env);
     }
   }
   return (obj: any);
 }
 
-function assertOverridesList(key: string, value: mixed): OverridesList {
-  const arr = assertArray(key, value);
+function assertOverridesList(loc: OptionPath, value: mixed): OverridesList {
+  if (loc.parent.type === "env") {
+    throw new Error(`${msg(loc)} is not allowed inside an .env block`);
+  }
+  if (loc.parent.type === "overrides") {
+    throw new Error(`${msg(loc)} is not allowed inside an .overrides block`);
+  }
+  const parent: RootPath = loc.parent;
+
+  const arr = assertArray(loc, value);
   if (arr) {
     for (const [index, item] of arr.entries()) {
-      const env = assertObject(`${index}`, item);
-      if (!env) throw new Error(`.${key}[${index}] must be an object`);
+      const objLoc = access(loc, index);
+      const env = assertObject(objLoc, item);
+      if (!env) throw new Error(`${msg(objLoc)} must be an object`);
 
-      validate("override", env);
+      const overridesLoc = {
+        type: "overrides",
+        index,
+        parent,
+      };
+      validateNested(overridesLoc, env);
     }
   }
   return (arr: any);