The Dayton Masonic Center, formerly known as the Dayton Masonic Temple, is a significant building in Dayton, Ohio.It was built by a Masonic Temple Association formed from 14 Masonic groups. The building was completed over a 2-year, 9-month period by 450 workers, "a majority of whom were Masonic Brethren", about which it was said: "Without thought of honor or gain, these men gave unstintingly of their time, abilities and means, sparing neither themselves nor their personal interests to advance this building project to its happy fulfillment."The building is 265ft long by 190ft wide by 80ft high, and encloses 5000000cuft. It is constructed of steel, cement, and stone, including 55,000cuft of Bedford stone and 15,000cuft hard limestone and marble from Vermont, Alabama and Tennessee ("marble used for interior floors, wainscotings, partitions and stairways").It is a contributing property in the Steele's Hill-Grafton Hill Historic District, a historic district that was added to the National Register of Historic Places in 1986. The building is also included in a locally designated historic district.