William N. Thompson House, also known as Old Governor's Mansion, is a historic home located at Indianapolis, Marion County, Indiana.

It was built in 1920, and is Georgian Revival style buff-colored brick mansion.

It consists of a two-story, five-bay, central section flanked by one-story wings.

It has a slate hipped roof and features a full width front porch and an elliptical portico at the main entry.

This article about a property in Marion County, Indiana on the National Register of Historic Places is a stub.