The Historic Mifflin House, a Wrightsville farmhouse that sheltered freedom seekers fleeing from slavery in the 1800s, joined the National Park Service’s Network to Freedom program last week.

The National Park Service has preserved and promoted more than 800 historical sites with connections to the Underground Railroad since the program launched in 1998. Visitors can find locations across 41 states; Washington, D.C.; the U.S. Virgin Islands; and Canada.

From 1810 to 1840, Quakers Jonathan and Susanna Mifflin took in dozens of freedom seekers on their farm, right across the Susquehanna River from Lancaster County. They usually hosted their guests for a few nights before the Mifflins, and later their son and inheritor Samuel, helped the freedom seekers cross the river northward, according to the Susquehanna National Heritage Area.

The property also witnessed a Civil War skirmish in Wrightsville , part of the 1863 Gettysburg Campaign.

The Mifflin House was one of three Pennsylvania sites added to the National Park Service’s Underground Railroad registry last week. Ten Lancaster County historical sites already participate in the program, including Old Lancaster County Jail and the First National Bank Museum in Columbia Borough.

The site will open to the public on a limited basis starting on May 24, and visitors can take tours on Saturdays, from 10 a.m. to 4 p.m., through October, according to the Susquehanna National Heritage Area.