William Penn's colony became a magnet for diverse migrants thanks to a rare combination of liberties and opportunities.
Penn, a Quaker, guaranteed liberty of conscience to all monotheists. Quakers, Mennonites, Amish, Catholics, Jews, and others found refuge from persecution.
Fertile soil (especially in the southeast), abundant timber, iron ore, and access to Atlantic trade via the Delaware River fueled farming, milling, and commerce.
Generous land grants and reasonable purchase terms allowed ordinary families to become landowners—a near-impossibility in Europe.
No established church; relative ethnic harmony; peaceful relations with Lenape natives (initially) created social stability.
The Frame of Government provided an elected assembly, trial by jury, and limits on proprietary power—unusually democratic for the era.
Letters home and promotional tracts painted Pennsylvania as a place where industry was rewarded and a better life was attainable.