Three people, two in suburban Maryland and one in the District of Columbia, were killed yesterday in automobile accidents, local authorities reported.

In the District, one man was killed and another was seriously injured early yesterday when their car plunged from an I-295 overpass and fell about 60 feet onto a railroad crossing, District police said.

Harry Butler, 42, of the 4300 block of Torque Street in Boulevard Heights, was killed in the 3:20 a.m. accident, police said. Authorities said Butler was a passenger in the car driven by James Dupree, 40, of the 6900 block of Danford Drive in Clinton. Dupree was listed in stable condition yesterday at Prince George's General Hospital with a concussion, a fractured jaw and possible spinal injuries.

Police said the auto, traveling north on I-295 at high speed, struck a barrier and plunged off the overpass about midway between the Pennsylvania Avenue and East Capitol Street interchanges.

Two as yet unidentified men died early yesterday after their car hit a bridge abutment on Aquasco Road in Prince George's county. The car was apparently traveling at high speed when the driver lost control, striking a bridge abutment sideways near the Prince George's County boundary with Charles County, police said.

The bodies of the two men were taken to the Baltimore Medical Examiner's office for autopsies.