diff --git a/packages/quicktype-core/src/input/JSONSchemaInput.ts b/packages/quicktype-core/src/input/JSONSchemaInput.ts
index 66b1c4104..a1aaddf94 100644
--- a/packages/quicktype-core/src/input/JSONSchemaInput.ts
+++ b/packages/quicktype-core/src/input/JSONSchemaInput.ts
@@ -544,7 +544,7 @@ class Canonizer {
 
         this.addIDs(
             schema,
-            new Location(Ref.root(address), Ref.root(undefined)),
+            new Location(Ref.parse(address), Ref.root(undefined)),
         );
         this._schemaAddressesAdded.add(address);
         return true;
diff --git a/test/fixtures.ts b/test/fixtures.ts
index 84616537e..007603afe 100644
--- a/test/fixtures.ts
+++ b/test/fixtures.ts
@@ -809,7 +809,38 @@ class JSONSchemaFixture extends LanguageFixture {
     }
 
     getSamples(sources: string[]): { priority: Sample[]; others: Sample[] } {
-        const prioritySamples = testsInDir("test/inputs/schema/", "schema");
+        const schemaDirectory = "test/inputs/schema/";
+        const multiFileSamples = fs
+            .readdirSync(schemaDirectory)
+            .map((entry) => path.join(schemaDirectory, entry))
+            .filter(
+                (entry) =>
+                    fs.statSync(entry).isDirectory() &&
+                    fs
+                        .readdirSync(entry)
+                        .some((filename) => filename.endsWith(".schema")),
+            );
+        const prioritySamples = testsInDir(schemaDirectory, "schema").concat(
+            multiFileSamples,
+        );
+
+        if (
+            sources.length === 1 &&
+            fs.lstatSync(sources[0]).isDirectory() &&
+            path.resolve(sources[0]) !== path.resolve(schemaDirectory)
+        ) {
+            return {
+                priority: [
+                    {
+                        path: sources[0],
+                        additionalRendererOptions: {},
+                        saveOutput: true,
+                    },
+                ],
+                others: [],
+            };
+        }
+
         const samples = samplesFromSources(
             sources,
             prioritySamples,
diff --git a/test/inputs/schema/issue-1833.1.fail.no-defaults.json b/test/inputs/schema/issue-1833.1.fail.no-defaults.json
new file mode 100644
index 000000000..1c7faa2ba
--- /dev/null
+++ b/test/inputs/schema/issue-1833.1.fail.no-defaults.json
@@ -0,0 +1,8 @@
+{
+    "a": {
+        "name": "root-a",
+        "in": [
+            { "name": "first" }
+        ]
+    }
+}
diff --git a/test/inputs/schema/issue-1833.1.json b/test/inputs/schema/issue-1833.1.json
new file mode 100644
index 000000000..cfef1715e
--- /dev/null
+++ b/test/inputs/schema/issue-1833.1.json
@@ -0,0 +1,15 @@
+{
+    "a": {
+        "name": "root-a",
+        "in": [
+            { "name": "first" },
+            { "name": "second" }
+        ]
+    },
+    "b": {
+        "name": "root-b",
+        "out": [
+            { "name": "third" }
+        ]
+    }
+}
diff --git a/test/inputs/schema/issue-1833/a.schema b/test/inputs/schema/issue-1833/a.schema
new file mode 100644
index 000000000..1ac0836bb
--- /dev/null
+++ b/test/inputs/schema/issue-1833/a.schema
@@ -0,0 +1,14 @@
+{
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "$id": "/schemas/a",
+    "type": "object",
+    "title": "A",
+    "properties": {
+        "name": { "type": "string" },
+        "in": {
+            "type": "array",
+            "items": { "$ref": "/schemas/c" }
+        }
+    },
+    "required": ["name", "in"]
+}
diff --git a/test/inputs/schema/issue-1833/b.schema b/test/inputs/schema/issue-1833/b.schema
new file mode 100644
index 000000000..ae9736303
--- /dev/null
+++ b/test/inputs/schema/issue-1833/b.schema
@@ -0,0 +1,14 @@
+{
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "$id": "/schemas/b",
+    "type": "object",
+    "title": "B",
+    "properties": {
+        "name": { "type": "string" },
+        "out": {
+            "type": "array",
+            "items": { "$ref": "/schemas/c" }
+        }
+    },
+    "required": ["name", "out"]
+}
diff --git a/test/inputs/schema/issue-1833/c.schema b/test/inputs/schema/issue-1833/c.schema
new file mode 100644
index 000000000..6d9351247
--- /dev/null
+++ b/test/inputs/schema/issue-1833/c.schema
@@ -0,0 +1,10 @@
+{
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "$id": "/schemas/c",
+    "type": "object",
+    "title": "C",
+    "properties": {
+        "name": { "type": "string" }
+    },
+    "required": ["name"]
+}
diff --git a/test/inputs/schema/issue-1833/top-level.schema b/test/inputs/schema/issue-1833/top-level.schema
new file mode 100644
index 000000000..f2932c40d
--- /dev/null
+++ b/test/inputs/schema/issue-1833/top-level.schema
@@ -0,0 +1,11 @@
+{
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "$id": "/schemas/top-level",
+    "type": "object",
+    "title": "TopLevel",
+    "properties": {
+        "a": { "$ref": "/schemas/a" },
+        "b": { "$ref": "/schemas/b" }
+    },
+    "required": ["a", "b"]
+}
diff --git a/test/languages.ts b/test/languages.ts
index 120f3170b..bc2963cfc 100644
--- a/test/languages.ts
+++ b/test/languages.ts
@@ -263,6 +263,10 @@ export const JavaLanguage: Language = {
     skipSchema: [
         "integer-before-number.schema", // Python-specific union-order regression.
         "keyword-unions.schema", // generates classes with names that are case-insensitively equal
+        // Multi-top-level directory input; the Java driver deserializes via the
+        // generic `Converter.fromJsonString`, which is only emitted for a single
+        // top-level (multi-top-level emits per-type `<Name>FromJsonString`).
+        "issue-1833",
         // The generated converter deserializes a top-level array with a raw
         // `List`, so a mistyped element round-trips instead of failing.
         ...skipsArrayElementValidation,
@@ -678,6 +682,9 @@ export const CJSONLanguage: Language = {
         /* Required properties absent are not checked (for the current implementation, can be added later, should abord parsing and return NULL) */
         "intersection.schema",
         "required.schema",
+        /* Multi-top-level directory input whose only negative case is a missing
+         * required property, which this renderer does not enforce (see above). */
+        "issue-1833",
         // The default-value fail sample also relies on required-property
         // enforcement, which cJSON does not do.
         "default-value.schema",
@@ -938,6 +945,9 @@ export const ElmLanguage: Language = {
         // The generated decoder accepts invalid union members because all
         // class properties decode via `Jpipe.optional`.
         "nested-intersection-union.schema",
+        // Multi-top-level directory input; the Elm driver decodes a single
+        // top-level named `QuickType`, which this fixture does not produce.
+        "issue-1833",
     ],
     rendererOptions: {},
     // `list` is the default now; keep the `Array` code path covered.
@@ -1012,6 +1022,9 @@ export const SwiftLanguage: Language = {
         "class-with-additional.schema",
         "vega-lite.schema",
         "top-level-primitive.schema",
+        // Multi-top-level directory input whose only negative case is a missing
+        // required property, which the Swift driver does not treat as a failure.
+        "issue-1833",
     ],
     rendererOptions: { "support-linux": "true" },
     quickTestRendererOptions: [
@@ -1082,7 +1095,13 @@ export const ObjectiveCLanguage: Language = {
         "combinations4.json",
     ],
     skipMiscJSON: false,
-    skipSchema: ["integer-before-number.schema"], // Python-specific union-order regression.
+    skipSchema: [
+        "integer-before-number.schema", // Python-specific union-order regression.
+        // Multi-top-level directory input; the Objective-C driver decodes a
+        // single top-level named `QTTopLevel`, which this fixture does not
+        // produce.
+        "issue-1833",
+    ],
     rendererOptions: { functions: "true" },
     quickTestRendererOptions: [],
     sourceFiles: ["src/language/Objective-C/index.ts"],
@@ -1921,6 +1940,9 @@ export const HaskellLanguage: Language = {
         // The default-value fail sample also relies on required-property enforcement.
         "default-value.schema",
         "required-non-properties.schema",
+        // Multi-top-level directory input; the Haskell driver decodes a single
+        // top-level named `QuickType`, which this fixture does not produce.
+        "issue-1833",
     ],
     rendererOptions: {},
     // The default is array-type=list; this keeps the Vector code path
@@ -2090,6 +2112,9 @@ export const TypeScriptZodLanguage: Language = {
         // The default-value fail sample also relies on required-property enforcement.
         "default-value.schema",
         "required-non-properties.schema",
+        // Multi-top-level directory input whose only negative case is a missing
+        // required property, which this fixture does not treat as a failure.
+        "issue-1833",
     ],
     rendererOptions: {},
     quickTestRendererOptions: [],
@@ -2209,6 +2234,9 @@ export const TypeScriptEffectSchemaLanguage: Language = {
         // The default-value fail sample also relies on required-property enforcement.
         "default-value.schema",
         "required-non-properties.schema",
+        // Multi-top-level directory input whose only negative case is a missing
+        // required property, which this fixture does not treat as a failure.
+        "issue-1833",
         "issue2680-top-level-array.schema",
     ],
     rendererOptions: {},
@@ -2285,6 +2313,9 @@ export const ElixirLanguage: Language = {
 
         // The generated top-level type is not emitted as a TopLevel module the fixture can call.
         "recursive-union-flattening.schema",
+        // Multi-top-level directory input whose only negative case is a missing
+        // required property, which Elixir cannot enforce at runtime (see above).
+        "issue-1833",
 
         // A top-level array is deserialized without enforcing its element
         // type, so a mistyped element round-trips instead of failing.
diff --git a/test/unit/json-schema-multiple-sources.test.ts b/test/unit/json-schema-multiple-sources.test.ts
new file mode 100644
index 000000000..1538b6941
--- /dev/null
+++ b/test/unit/json-schema-multiple-sources.test.ts
@@ -0,0 +1,42 @@
+// The fixture runner exercises this multi-file input end to end, but duplicate
+// structural interfaces still compile.  Assert here that the dead interface is
+// not generated.
+import * as fs from "node:fs";
+import * as path from "node:path";
+
+import { InputData, JSONSchemaInput, quicktype } from "quicktype-core";
+import { describe, expect, test } from "vitest";
+
+const fixtureDirectory = "test/inputs/schema/issue-1833";
+
+async function generateTypeScript(): Promise<string> {
+    const schemaInput = new JSONSchemaInput(undefined);
+    for (const filename of ["a.schema", "b.schema", "c.schema"]) {
+        const fixturePath = path.resolve(fixtureDirectory, filename);
+        await schemaInput.addSource({
+            name: path.basename(filename, ".schema"),
+            schema: fs.readFileSync(fixturePath, "utf8"),
+            uris: [fixturePath],
+        });
+    }
+
+    const inputData = new InputData();
+    inputData.addInput(schemaInput);
+    const result = await quicktype({
+        inputData,
+        lang: "typescript",
+        rendererOptions: { "just-types": true },
+    });
+    return result.lines.join("\n");
+}
+
+describe("JSON Schema multiple sources (issue #1833)", () => {
+    test("a top-level schema and references to its $id share one type", async () => {
+        const output = await generateTypeScript();
+
+        expect(output).toContain("in:   C[];");
+        expect(output).toContain("out:  C[];");
+        expect(output.match(/export interface C/g)).toHaveLength(1);
+        expect(output).not.toContain("export interface InElement");
+    });
+});