UPCOMING EVENTS SEE ALL FNBO - Longmont/Main St. Share: Banks & Banking Services FNBO - Longmont/Main St. Visit Website 2305 Main Street Longmont, CO 80501 (303) 308-3838 About Map About We’ve been building relationships with our customers in Colorado since 1994 and today we serve more than 16 communities. What's Nearby? Distance: 5 10 15 20 25 50 mi.