Caernarvon Township is a township in northeastern Lancaster County, Pennsylvania, United States. For the 2020 census, the population was 4,605.

Lancaster County, sometimes nicknamed the Garden Spot of America or Pennsylvania Dutch Country, is a county in the Commonwealth of Pennsylvania. As of the 2020 census, the population was 552,984, making it Pennsylvania's sixth-most populous county. Its county seat is also Lancaster. Lancaster County comprises the Lancaster metropolitan statistical area. The county is part of the South Central region of the state.