Church of St. William 1351 Main St, Tewksbury, MA01876 St. William Catholic Church, under the leadership of Fr. John Hanley, OMI, is celebrating its 75th anniversary in 2010.…More The largest church in Tewksbury, St. William has approximately 3,900 local families on its rolls. The picturesque campus includes the sancturay, rectory, activity hall and the former St. William School. Founded by the Oblates of Mary Immaculate, St. William has active men's women's and youth ministries. The church also plays host to the Troop 49 Boy Scouts and Pack 49 Cub Scouts.