Blairstown is a Township in Warren County, New Jersey, United States. As of the 2010 United States Census, the township population was 5,967. Blairstown Township was incorporated as a township by an Act of the New Jersey Legislature on April 14, 1845, from portions of Knowlton Township, based on the results of a referendum held that day. It is located in Warren County, New Jersey.
- Historic Blairstown Theater (also known as Roy's Hall) was built in 1913 as a silent movie house. The building was restored and painted blue in 2005 and was the site of the Blairstown Theater Festival in 2007.
- Happiness is Camping, which was called Camp Gramercy before 1980, is a campground that provides free summer camp to children with cancer and their siblings.