Last Mountain Lake, also known as Long Lake, is a large prairie lake in south-central Saskatchewan, formed by glaciation approximately 11,000 years ago. Located about 40 kilometres northwest of Regina, the lake stretches roughly 93 kilometres in length and averages about 3 kilometres in width, placing it within the Qu'Appelle River drainage basin. It is the largest naturally occurring body of water in southern Saskatchewan, with an area of approximately 231 square kilometres. The lake's elongated, narrow shape means paddlers are rarely far from shore, but the sheer length creates significant open-water exposure to wind and waves — a primary consideration for trip planning on this lake.

Several access points exist around the lake. On the eastern shore, Rowan's Ravine Provincial Park features a marina and is noted as a stop-over point for recreational boaters travelling along the lake. Regina Beach on the southern end is a commonly used launch site, though local paddlers have noted that Rowan's Ravine is generally preferred over Regina Beach for launching. Alice Beach and Henderson Beach at Big Arm Bay are also launch options on the west side, with Henderson Beach charging a small fee payable at a mailbox and offering no services or washrooms.

The lake supports a notable wildlife dimension: it is recognized as a bird sanctuary and a stopping point on a major flyway, with whooping and sandhill cranes passing through during spring and fall migrations. This makes the shoulder seasons of particular interest for paddlers with an interest in wildlife observation.

Fish species present include northern pike, walleye, perch, whitefish, carp, and buffalo fish. Fishing activity on the lake is substantial, including a large walleye tournament held at Rowan's Ravine each September, so paddlers should be aware of increased motorized boat traffic during such events.

Facilities along the lake include campgrounds, a restaurant, mini-golf, and a beach at Rowan's Ravine Provincial Park, as well as boat launches at multiple locations. Last Mountain Regional Park, situated near the northern end of the lake, also provides a boat launch, parking, and a fish filleting station. The lake is surrounded by numerous resort communities and regional parks, meaning paddlers have reasonable access to amenities along much of its length.