Usonia Historic District is a planned community and national historic district in the Town of Mount Pleasant, adjacent to the village of Pleasantville, Westchester County, New York. In 1945, a 100-acre rural tract was purchased by a cooperative of young couples from New York City, who were able to enlist the students of Frank Lloyd Wright to bui…Usonia Historic District is a planned community and national historic district in the Town of Mount Pleasant, adjacent to the village of Pleasantville, Westchester County, New York. In 1945, a 100-acre rural tract was purchased by a cooperative of young couples from New York City, who were able to enlist the students of Frank Lloyd Wright to build his Broadacre City concept. Wright decided where each house should be placed. Wright designed three homes himself and approved architectural plans of the other 44, which were designed by such architects as Paul Schweikher, Theodore Dixon Bower, Ulrich Franzen, Kaneji Domoto, Aaron Resnick and David Henken – an engineer and Wright apprentice.