Hayden House, also known as, "La Casa Vieja," or, "The Old House," is a historic building and landmark in Tempe, Arizona, and is the oldest occupied structure in the Salt River Valley (more commonly, The Valley of the Sun[3]).

[4] Built in 1873, the home originally belonged to Charles Trumbull Hayden, who founded the city of Tempe.

The home started out as a 13-room Mexican adobe style structure and saw an addition of two rooms by 1876.

[4] It was later renovated to add an additional six rooms to the main floor and a two-room second story.

[7] As of summer 2020, the Hayden House has nearly been rehabilitated to its 1924-era state by Hensel Phelps as a condition of further development on the site (see 100 Mill).