Nighttime in Upper Marlboro: Dark windows. Empty streets. Did you hear that lonesome whippoorwill?

Upper Marlboro is the seat of Prince George's County, a town devoted almost solely to the operation of the county government. By day, it is a thriving area of several thousand county workers, minor traffic tangles and coveted parking space.

But the crowds who come to town to work and do business with the county do not linger. By late afternoon, their evacuation is well under way.

Cars spill out of the parking lots near the courthouse and the county administration building, bound for the surrounding communities of Nottingham and Landover and Croom. The lone police officer, a servant of imposing girth, claps shut his ticket book and heads home.

Soon, the town is left largely to its 828 residents and its more reluctant population -- about 500 detainees at the county jail. Soon, the town is so still that the major traffic light at Main and Water streets changes with an audible click.

"We're one of the last places around that rolls up the sidewalks at night," said Joyce Sweeney, a native who is an assistant to the County Council.

By most standards, Upper Marlboro is a curious holdout. Nine miles from the Beltway and an easy 20 miles from the District, it was spawned by the same county that produced the urban sprawl of Capitol Heights and the pizza-stained academia of College Park.

Nevertheless, on a recent Friday night, the town looked somewhat like an abandoned Hollywood set.

Main Street, a collection of small stores, sandwich shops and attorneys' offices, was virtually deserted. A pool of pale yellow light illuminated the empty loading dock of the post office. The county administration building, a large white structure patterned after the Kennedy Center, was a brightly lit shell. At nearby Schoolhouse Pond, the frogs made a fitful chittering sound.

But surely the town couldn't be as dead as it looked? Surely there was light and laughter somewhere in Upper Marlboro?

Perhaps at the Coin-Operated Laundry, one of the few establishments open after dark.

J.J. Jones, a grizzled construction worker who refused to give his age, stood in the lighted doorway of the laundry.

"I just come here to wash my clothes, that's my only business here," said Jones, who lives in Forestville.

"Soon as my clothes dry," he said, "I'm gone."

Jones had few insights to offer on night life in Upper Marlboro. "Looks dead as a doornail to me," he said. "Try over at High's. Maybe they know something."

High's convenience store, open until midnight, is the undisputed king of after-hours dining in Upper Marlboro. No fast food chains have yet intruded on the town.

"Yes, I guess we're one of the main attractions," said clerk Joyce Bowen, as she waited on a middle-aged man in shirt sleeves with a beeper attached to his belt. The customer grabbed the bag containing his purchases -- a submarine sandwich, a can of V-8 juice, a pack of cigarettes -- and disappeared out the door.

"But if you really want to know what goes on at night around here," Bowen continued, "you ought to go up to the liquor store."

West End Liquors is one of two liquor stores in Upper Marlboro. Edelen Liquors, at the opposite end of Main Street, closes shortly after the day's sale of lottery tickets ends at 8 p.m.

The West End store, distinguished by orange and green neon arrows, is open until 9. Inside, clerk Charles Fletcher, 62, leaned on the wooden counter. A customer rummaged through the beer cooler.

Very busy tonight? "I'll see five people. An hour passes and I'll see two more," Fletcher said, in a voice so dry it crackled.

Anything interesting happening? "Not a thing," he said.

Does anything interesting ever happen? Fletcher snorted in reply.

Any other observations on Upper Marlboro after dark? "That's about it," he said, shaking his head. "What you see is what you get."

Out on the street again, a black and white cat sauntered down the sidewalk, a solitary pedestrian. A shadow moved behind the blinds in an attorney's office -- someone working late. Clothes tumbled in the dryers at the Coin-Operated Laundry.

But wait, headlights were now visible in the distance, bearing down on the town of Upper Marlboro. A beige Plymouth pulled to a halt on Main Street. The driver's door opened slowly.

A woman wearing bedroom scuffs got out and padded over to the blue mailbox in front of the post office. She dropped a stack of letters in, padded back to her car, and drove off.