Riordan Mansion State Historic Park, Arts and Crafts mansion in Flagstaff, United States.

Riordan Mansion State Historic Park preserves a 13,000-square-foot duplex built in 1904, with two 6,000-square-foot wings joined by a large common room. Architect Charles Whittlesey, who also designed the El Tovar Hotel, used log planks, wood shingles and native stone; massive stone arches mark the porch corners. The two-story facade has a projecting stone porch with a large window and a stone base of stacked flat rocks pierced by two round arched openings.

The Riordan brothers, who ran a lumber business in Flagstaff, had the residence completed in 1904 as a sign of their success. The architect Charles Whittlesey, who also designed the El Tovar Hotel at the Grand Canyon, drew up the plans.

The rooms still hold their original furnishings and handcrafted objects, showing how a prosperous family lived in early 1900s Arizona. Walking through the spaces, you come across personal items that give a direct sense of the daily habits and tastes of that era.

The interior can only be visited on a guided tour, so booking ahead is a good idea, especially during busy periods. The grounds are in central Flagstaff and easy to reach on foot from the downtown area.

The two halves of the building were deliberately kept separate inside, so each family had a complete and independent home of their own. The shared hall in the middle was the only space both families used regularly together.