Middletown is a borough in Dauphin County, Pennsylvania, on the Susquehanna River, 10 miles (16 km) southeast of Harrisburg.

Middletown was selected as the western terminus of the Union Canal, and it was named from its location halfway[5] between Lancaster and Carlisle, where an ascent exists to a low pass allowing easier wagon-era travel[6] among the barrier mountains of the Ridge-and-valley Appalachians giving access into north-central Maryland and the valley of the Potomac River.

[a] It is the oldest incorporated community in Dauphin County and is located within a rich agricultural area forming the western edge of Pennsylvania Dutch Country.

The orphanage eventually closed, and the final location, on Red Hill, has become the Frey Village Retirement Community, a Diakon Lutheran senior living facility.

The Unit #2 reactor at the Three Mile Island Nuclear Power Plant suffered a partial meltdown in 1979, causing then Pennsylvania governor Dick Thornburgh to order the evacuation of pregnant women and pre-school children from the area.

[7][8] President Jimmy Carter visited Middletown's Community Building to calm the nerves of anxious residents.

Middletown has everything from log houses, some whose construction is obscured by modern siding, to Victorian mansions, and beyond.

The Pennsylvania Turnpike (Interstate 76) passes through the northern part of the borough, but the nearest access is 4 miles (6 km) west near Highspire.

The Middletown Area Historical Society is both a museum and visitor center located at 29 East Main Street.

Indian Echo Caverns, located 5 miles north of the borough limits, is one of the main attractions near Middletown.