This is a Bomarc A surface-launched, pilotless interceptor missle built to destroy enemy aircraft. Called "Bomarc" for Boeing and Michigan Aeronautical Research Center, it was launched and powered by a liquid-fueled rocket booster, at least until it reached a high-enough speed for its ramjets to kick in.
"It was guided from the ground to the vicinity of its target, at which time it came under control of an internal target seeker," reads an information sign at the Hill Aerospace Museum.
The first prototypes were tested in 1952, and the Bomarc A came online in 1960, hosted at five Air Force bases in the northeastern United States. It was housed inside large shelters that had sliding roofs; the missile would be positioned vertically for launch.
The Bomarc A was operational until the mid-1960s. It was 47 feet 4 inches long, weighed 15,619 pounds at launch and could travel at Mach 2.8 for 260 miles. It carried either a W-40 nuclear warhead or a 1,000-pound high-explosive warhead.