Holy Trinity Church, also known as Old Swedes is a National Historic Landmark. It was dedicated on July 4, 1699.
The church was built in 1698-99 in the Swedish colony of New Sweden from local blue granite and Swedish bricks that had been used as ship's ballast. The church was situated on the site of the Fort Christina's burial ground, which dates to 1638. It is claimed that it is "the nation's oldest church building still standing as originally built". There are reportedly over 15,000 burials in the churchyard. Lutheran Church services were held in the Swedish language well into the 18th century.
The church has housed an Episcopal parish since 1791 and is now part of the Episcopal Diocese of Delaware. An earlier church in New Sweden was built in Swanwyck, near New Castle about 1662 which was replaced by a combined church and fort at Crane Hook in 1667.