Marsh Lake sits at the northern end of the Southern Lakes chain in Yukon, Canada, approximately 45 minutes south of Whitehorse via the Alaska Highway. It holds geographical significance as the most northerly of a 600-kilometre chain of interconnected lakes and forms part of the headwaters of the Yukon River. The lake has a resident population of around 683, with a mix of year-round residents and cottage owners along portions of its shoreline.

For paddlers, Marsh Lake serves primarily as a starting point for downstream travel on the Yukon River rather than as a destination paddle in itself. Canoe and kayak rentals are available through Inn on the Lake, which sits on the lake's shores and offers complimentary watercraft to guests. The paddling season generally runs from May through October. Army Beach, a large crescent of sandy shoreline, provides a campground, picnic area, playground, and boat launch. Judas Creek Marina also offers a boat launch, available through an annual membership.

The most popular paddling route originating at Marsh Lake is the Yukon River downstream to Whitehorse — a 30-kilometre stretch that is fast-flowing, requires no portages, and can be completed in a single day. This section is considered suitable for beginners. For those with more time, the full run from Marsh Lake to Dawson City covers 752 kilometres by river, passing through Whitehorse, Lake Laberge, Five Finger Rapids, and Fort Selkirk. Shuttle services to Marsh Lake are available through outfitters Up North Adventures and Kanoe People in Whitehorse.

Wildlife viewing is a notable draw on and around the lake. Approximately 10 percent of all Trumpeter Swans in North America stop at Marsh Lake during the annual spring migration, an event celebrated locally each April. Moose sightings are also reported in the area.

Marsh Lake carries considerable historical weight as part of the Klondike Gold Rush route of 1897–98. Gold seekers who crossed the White Pass would build rafts at the lake and float downstream toward Dawson City. The lake also sits within a region historically used as a trading corridor by Southern Tutchone and Tlingit peoples.