The only ORVIS fly fishing endorsed outfitter on the San Juan River quality waters. Fisheads is the premiere fly fishing guide service on the San Juan River. Join Fisheads San Juan River Lodge on the San Juan River for the fly fishing experience of your life! Cast to trophy sized trout 365 days a year. Fisheads is the premiere fly fishing guide service on the San Juan River. Located in the northwest corner of New Mexico, the San Juan River is world renowned for providing some of the most rewarding trout fishing you will ever experience. The San Juan is a consistent producer of both rainbows and browns averaging 16 to 18 inches, with many reaching much larger proportions. The San Juan River is a significant tributary of the Colorado River in the southwestern United States, about 383 miles (616 km) long. The river drains an area of about 24,600 square miles (64,000 km2) in southwestern Colorado, northwestern New Mexico, southeastern Utah, and a small part of northeastern Arizona. The average flow of the San Juan River at Bluff is about 2,200 cubic feet per second (62 m3/s) and the highest discharge ever measured was about 70,000 cubic feet per second (2,000 m3/s) on September 10, 1927.