Erwinna is an unincorporated community located in Tinicum Township, Bucks County, Pennsylvania, United States, with a zip code of 18920. At the 2000 Census the population was 577. It is named after Colonel Arthur Erwin (also "Irwin"), who was a leader in the Bucks County Militia. A concise biography of him has been created by the DAR Chapter bearing his name. Colonel Erwin is said to have supplied many of boats that were used by George Washington and the Continental Army to cross the Delaware on the night of December 25, 1776, en route to the Battle of Trenton the following morning. It is pronounced exactly as it as spelled, "er-WIH-na", though it is sometimes mispronounced "er-WEE-nuh" or "er-WAH-na".