Naturally formed, Diamond Lake is located near the junction of Hwy 138 (North Umpqua Hwy) and Oregon Route 230 (which follows the Rogue River) in the Umpqua National Forest. Named after John Diamond, a pioneer settler of the area, it was first spotted by Diamond from Diamond Peak (also named for the settler) in 1852.
The Diamond Lake area offers a large variety of outdoor activities that can be enjoyed year round. The winter and early spring months bring snowmobiling, cross country skiing, a downhill snow tubing slide, and ice fishing. Summer brings about camping, hiking, horseback riding, biking, hunting, boating and of course fishing.
Diamond Lake does not naturally produce the required habitat for spawning fish but produces a large population of aquatic insects making an ideal feeding ground for fish. Because of the lack of spawning grounds for sport fishing, the Oregon Department of Fish and Wildlife (ODFW) began stocking the lake in 1954 with rainbow trout. Prior to stocking the lake the ODFW treated the lake to rid it of rough fish (also known as trash fish or those fish not desirable for sport fishing or consumption). Prior to the early 1990's, it was not uncommon for anglers to catch rainbow trout in the 10 pound range and the average fish caught weighed in excess of one pound.
In 1992, a non-native species of fish known as the tui chub was found in the lake. These fish were illegally into the lake most likely when used as live bait fish. They quickly multiplied and severely effected the rainbow trout population. It also had negative impacts on the water quality of the lake and the insect population necessary to the region. In 2006 the ODFW drained the lake to a very low level and poisoned the tui chub, 95 million of them, in an effort to improve the quality of the lake and it's rainbow trout population. By 2007 there were dramatic improvements in the water quality, insect population and trout catches. In January 2016 a plan was revealed to release up to 25,000 fish-eating tiger trout into the lake after a single tui chub was found. This is being done in hopes of stopping another infestation of non-native bait fish in the lake.
Fishing in Diamond Lake can be done by boat or from the banks of the lake in the spring and summer months. Most anglers are successful with the use of power bait or small lures, depending on the area of the lake they are fishing.
In January of 2013 Diamond lake opened up to year round fishing by including the option to ice fish on the lake. Anglers have been successful using standard ice fishing jigs, worms and power bait when fishing on the ice.