Sporley Lake is a 77-acre pothole lake in Marquette County, Michigan, featuring relatively steep contours and a maximum depth of 42 feet. Located east of the former K.I. Sawyer airbase, the lake has remained largely undeveloped with a shoreline similar to what existed 100 years ago.

The public access site consists of an unimproved gravel shoreline with a courtesy pier and parking for approximately 5 vehicles with trailers. A outhouse is available at the access point. The lake's water clarity is notable, with secchi disk readings of 22 feet recorded.

A large shoal along the north shoreline, 10-15 feet deep, creates a littoral zone comprising about 25% of the total surface area. The lake develops a thermocline around 22 feet in summer months. Water quality testing has shown relatively low alkalinity (8 mg/l), indicating soft water conditions.

Recent paddler reports note that the lake can experience boat and jet ski traffic that creates wakes, particularly in deeper areas. The shallower ends of the lake offer calmer conditions and good fishing opportunities. The lake's water can display brilliant turquoise and bluish-green colors similar to Torch Lake and Glen Lake.

The watershed is very small, consisting mainly of direct runoff from adjacent uplands and likely some underwater springs. The surrounding landscape features gently rolling hills of coarse glacial remains with sandy and gravelly substrate. Dense mixed forest dominated by maple, with birch, pine, and spruce creates the backdrop.

The lake has experienced periodic water level fluctuations, with local concerns about the impact of nearby well withdrawals on lake levels. A small, intermittent outlet flows northwest into Big Trout Lake.