Small Hall is located on Ukrop Way between the Earl Gregg Swem Library and Jones Hall. William & Mary broke ground for the 778,000-square-foot building in August 1962. The building is named for William Small, a professor of Natural Philosophy and mentor to Thomas Jefferson while a student. The building was completed in December 1963 and has been in use since February 1964. Small Hall is currently the home of the Department of Physics and the Physics Library.

A twelve-foot observatory dome housing a ten-inch reflecting telescope was built on the roof in 1975. The observatory was named the Thomas Harriot Observatory after the first astronomer in Virginia who accompanied Raleigh's expedition from 1585 to 1586. A 6,800 square-foot, two-story addition was added to Small Hall between March and November 1985, containing ten faculty offices and a two-story library.

A project to install a large, high field NMR magnet was completed in 2005 and is one of the largest in the state. From 2008-2011, a large renovation project took place that installed solar panels on the roof, created more lab space, and added a Faraday cage to shield against external electromagnetic radiation.