Hallam HEL-əm is a borough in York County, Pennsylvania, United States. The population was 2,673 at the 2010 census.
Before 1736, all parts of Pennsylvania west of the Susquehanna River, including present-day Hallam Borough and the surrounding Hellam Township, were land of the Iroquois.
In October 1736, the Proprietors of Pennsylvania received from the Five Nations deeds for the Susquehanna lands south of the Blue Mountains, including the borough and township.
From 1736 to 1739, the area was under the authority of Hempfield Township in Lancaster County east of the Susquehanna. In 1739, the Provincial Assembly passed a special act to empower Lancaster County to establish townships west of the river. Hellam Township was created and included most of what is now York, Adams and Cumberland counties. Hellam Township was named after Hallamshire, the township in England where Samuel Blunston, the magistrate of Lancaster County, was born.
When Hallam Borough was incorporated in 1902, the town's name was spelled Hallam, the same as the English township.
The Martin Schultz House was listed on the National Register of Historic Places in 1993.
Hallam is located at 40°0′14″N 76°36′16″W (40.003897, -76.604528). It is a suburb of York, Pennsylvania and is part of the York-Hanover Metropolitan Statistical Area, as well as the York-Hanover-Gettysburg Combined Statistical Area.
According to the United States Census Bureau, the borough has a total area of 0.7 square miles (1.8 km2), all of it land.
Hallam is located within the Kreutz Creek watershed.
Hallam lies on the cusp of a humid subtropical climate zone and experiences four discernible seasons.