Thornhurst Addition, Historic residential district in Carmel, United States.

Thornhurst Addition is a national historic district in Carmel, Indiana, with 21 contributing buildings and one contributing site in a mainly residential section. Its houses, built between about 1956 and 1971, show Modern Movement design by architect Avriel Shull, including post and beam construction, large aluminium window expanses, slate or stone entry floors and clerestory windows.

The neighborhood developed between 1956 and 1971 and earned recognition on the National Register of Historic Places in June 2010. This designation marks its importance to post-war residential development in the region.

Thornhurst Addition takes its name from the Thornhurst Drive that runs through it, and its houses were designed by Avriel Shull (1931–1976), an Indianapolis architect who worked largely on her own commissions. Visitors can spot her signature post and beam frames, wide aluminium window walls, slate or stone entry floors and clerestory windows on the 21 contributing buildings.

The district is easiest to access via West Main Street and Thornhurst Drive, which provide clear routes through the area. Walking through the neighborhood allows you to see the homes' details and architectural features up close.

Each home features distinctive clerestory windows and slate entry floors that show the design thinking of this post-war era. These architectural details were deliberate choices to support the modern way of living that homeowners wanted at the time.