Brandywine Creek (also called the Brandywine River) is a tributary of the Christina River in southeastern Pennsylvania and northern Delaware in the United States. The Lower Brandywine is approximately 17 mi (27 km) long, and is a designated Pennsylvania Scenic River with several tributary streams. The East Branch and West Branch of the creek originate within 2 mi (3 km) of each other on the slopes of Welsh Mountain in Honey Brook Township, Pennsylvania about 20 mi (32 km) north of their confluence. The mouth of the creek on the Christina River in present day Wilmington, Delaware is the site of the New Sweden Colony, where colonists first landed on March 29, 1638. The Battle of Brandywine was fought around the creek near Chadds Ford, Pennsylvania on September 11, 1777, during the American Revolution. Water powered grist mills in Brandywine Village, near the creek mouth, and the nearby DuPont gunpowder mill were important in developing American industry before the introduction of steam power.