Guaranty Bank and Trust Company, Longmont Branch Basic Info Reviews Routing Numbers Map & Direction Name: Guaranty Bank and Trust Company, Longmont Branch Main Office: No Service: Full Service Brick and Mortar Office Location: 401 Main Street Longmont, Colorado 80501 Boulder County View other branches Phone: 303-682-8906 Please enable JavaScript to view the comments powered by Disqus. Routing NumberProcess ACH TransferProcess Wire Transfer102000966YY107000628YN107002163YN107003667YN107004611YN107004776YY107005982YN107006363YN From: To: