Four Mile Lake has an area of 593 acres and has a maximum depth of 19.5 feet although the majority of the lake is less than 15.0 feet deep. Water clarity was poor with visibility measured to five feet in the brown bog-stained water. The shoreline around the lake is mainly covered in a mixture of deciduous and coniferous forest with the southwestern bay having marsh and bog covered shoreline. The majority of the shoreline is under public ownership with a small portion being private ownership. The aquatic and riparian plant community is diverse with 42 types of aquatic and riparian plants present during the 2016 survey. Most of the main basin of the lake has a ring of hardstem bulrush and spikerush growing near the shore. The southwestern bay is shallow and supports a dense bed of wild rice, which brings a variety of duck species to the lake. Sand is the most common substrate present followed by gravel and rubble. Walleye, Black Crappie, Yellow Perch, and Northern Pike are the most common game fish in the lake.
Four Mile Lake is located 10 miles northwest of Tofte, MN off of USFS Road 170 (The Grade). There is a U.S. Forest Service concrete ramp with a small dock located at the north end of the lake. The access in is located within the four site Forest Service campground, and there is parking for at least five vehicles with trailers. In addition to the campground, there are three remote water access campsites located along the shore of the lake. The campground and remote campsites get a large amount of use during the summer and the lake is well suited for a variety of watercraft from medium size boats and pontoon boats to canoes and kayaks. There are many boulders submerged just under the surface that are difficult to see in the dark water so caution should be used when boating on the lake.
The 2016 standard survey was conducted to observe the aquatic habitat and fish populations in Four Mile Lake. Investigations have been performed on the lake on a five year rotation to monitor the fish populations and the 2016 survey was the fourth investigation performed on this rotation schedule.
During the 2016 survey, Walleye catch was above average relative to similar lakes in the Northeastern Minnesota. The average length of Walleye was 13.94 inches with an average weight of 1.18 pounds. Twenty-eight percent of the catch was over 15.00 inches long. The largest Walleye sampled was 25.98 inches long and weighed 5.73 pounds. Thirteen year classes were represented in the 2016 survey indicating consistent recruitment to the population. Walleye growth was average for the Finland Area.
Black Crappie were sampled in low numbers for the lake class. One Black Crappie was caught in the gill nets and measured 4.49 inches long and weighed 0.06 pounds. The trap nets sampled one Black Crappie, which measure 11.02 inches long and weighed 0.92 pounds. Small mesh trap nets collected five adult Black Crappie and 698 young-of-the-year Black Crappie. There were two Black Crappie caught in the small mesh nets that measured over 10.00 inches long with the largest measuring 11.81 inches. Four year class were present in the sample based on scale aging, but with the low number of Black Crappie sampled growth cannot be precisely determined. Black Crappie lakes in the Finland Area tend to have small populations of fast growing fish that may have an occasional strong year class. The spawning habitat in Four Mile Lake appears to be good, but the cool climate of the northeastern Minnesota may be a limiting factor in successful reproduction.
The Yellow Perch gill net catch was below average for similar lakes in the Northeastern Minnesota. This was the second consecutive survey to sampled Yellow Perch at below average numbers in gill nets. Even with the lower than average numbers the average weight of Yellow Perch in the gill nets was 0.53 pounds, above average for similar lakes and average length was 9.66 inches. Yellow Perch were sampled at average numbers with trap nets and had an average weight of 0.43 pounds (8.64 inches), which was above average for other lakes in the Finland Area. The largest Yellow Perch sampled in 2016 was 13.07 inches long (1.15 pounds). Seven year classes were sampled based on scale and otolith aging and growth of Yellow Perch appears to be average for the Finland Area
The 2016 Northern Pike catch was below average for lakes in the Finland Area with only 11 fish sampled. The average weight of the Northern Pike sampled was 2.06 pounds and average length was 20.57 inches. The largest Northern Pike caught was 27.36 inch long and weighed 4.41 pounds. Six year classes were present in the sample and growth of Northern Pike appears to be average for the Finland area. Northern Pike, over the last four surveys, have been sampled at low numbers even with the lake presumed to have good spawning habitat for Northern Pike.
White Sucker were sampled at average numbers relative to similar lakes. The average length of White Sucker was 16.69 inches and just over 2.00 pounds in weight. Fourmile Creek is a popular spot for spearing White Sucker in the spring. Small mesh trap nets also sample Blacknose Shiner, Tadpole Madtom, and unidentified minnows.
Four Mile Lake is a good Walleye lake with decent numbers of eater size Walleye in the population. The lake also has a good number of large Yellow Perch that anglers may consider targeting. Besides the fish populations bringing anglers to the lake, the abundant wild rice in the southwest bay draws in ducks and duck hunters in the fall, and the campground is a popular spot for bear hunters. The lake is also used by kayakers and canoes that just want to get out on the water on this scenic lake.