I know New England churches had a long history, but this one's older than most. According to its website, the First Congregational Church of Guilford was founded in 1643. Like many Congregational churches, it went through various religious changes. Today, it is part of the United Churches of Christ. Of course the building isn't quite that old. According to a history of the church, the current church dates to 1830 It has features typical of the period, although some are 1930s era replacements. According to that history, the steeple was lost in the 1938 hurricane. This mix of architectural and social history created a legacy that influenced all the surrounding towns.
Why? Because many were formed from Guilford. That means your colonial and early American ancestors may actually have a church record in Guilford. To access them, you'll probably want to start with the Connecticut State Library's slip index or a microfilm from the Family History Library. But read carefully. Many towns split off in the 1700s. You can read each church's records to find the foundation date or work in the opposite direction and look for the splits.