diff --git a/web/src/narrow_state.ts b/web/src/narrow_state.ts
index c08f9ff5e1..f5ee6a1221 100644
--- a/web/src/narrow_state.ts
+++ b/web/src/narrow_state.ts
@@ -130,7 +130,10 @@ export let stream_id = (current_filter: Filter | undefined = filter()): number |
     }
     const stream_operands = current_filter.operands("channel");
     if (stream_operands.length === 1 && stream_operands[0] !== undefined) {
-        return Number.parseInt(stream_operands[0], 10);
+        const id = Number.parseInt(stream_operands[0], 10);
+        if (!Number.isNaN(id)) {
+            return id;
+        }
     }
     return undefined;
 };
diff --git a/web/tests/narrow_state.test.cjs b/web/tests/narrow_state.test.cjs
index 42f5d0132c..feb1a1032b 100644
--- a/web/tests/narrow_state.test.cjs
+++ b/web/tests/narrow_state.test.cjs
@@ -40,6 +40,15 @@ test("stream", () => {
     assert.ok(!narrow_state.filter());
     assert.equal(narrow_state.stream_id(), undefined);
 
+    // hash_util.decode_operand returns an empty string when
+    // stream_data.slug_to_stream_id returns undefined, e.g., the
+    // stream name in the URL no longer exists or is inaccessible.
+    set_filter([["channel", ""]]);
+    assert.ok(narrow_state.filter());
+    assert.equal(narrow_state.stream_name(), undefined);
+    assert.equal(narrow_state.stream_id(), undefined);
+    assert.equal(narrow_state.stream_sub(), undefined);
+
     const test_stream_id = 15;
     const test_stream = {name: "Test", stream_id: test_stream_id};
     stream_data.add_sub(test_stream);