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Diamond Lake

Cass County, Michigan Inland Lake Connected Water
1 launchRec Passport required
Diamond Lake Access Map 1 launch
🎣 Fishing Guide → Click markers for details
Boat Launches on Diamond Lake
Diamond Lake Boat Launch
Cassopolis Field Office · Unimproved ramp, 2 lanes, 60 trailer spots
Open Motorboat Kayak Rec Passport
View ramp details →
Connected Waterways

Christiana Creek drainage (St. Joseph River watershed)

Winter & Ice Safety

Ices most winters with a strong local ice community — panfish and pike through the hard water. The island's wind shadows create uneven ice; the channels between island and shore demand respect.

Frequently Asked Questions
Can you visit Diamond Island?
The island is private cottage ground — one of Michigan's largest inland-lake islands, with a boat-access community that's summered there for over a century. Boaters circle it (the structure around it fishes well) but landing is by invitation. It's the lake's signature view from every shore.
Scout's Notes
Lake Vibe & Fishing Intel

Diamond Lake is Cass County's flagship: a thousand-plus acres of clear, hard-bottomed water at Cassopolis with a genuine rarity in its middle — Diamond Island, one of the largest islands on any Michigan inland lake, ringed by its own cottage colony reachable only by boat. The lake's resort history runs back to the rail era, when Chicago money summered here; the water-ski clubs, sailing fleet, and busy summer weekends carry that DNA forward.

It fishes better than its social calendar suggests: smallmouth on the rock and sand structure, largemouth in the shallower bays, pike on the edges, and strong panfish — with the public access putting working anglers on water the cottages otherwise dominate. Early mornings and the shoulder seasons belong to the fishermen; summer midday belongs to the wakes.

Sources: PRDBAS (access facility), Cass County context, regional lake history