Determining a basin on a lake?

[MnMike]

so many folks talk about locating a basin or picking the right basin in a lake to fish, i was wondering what peoples opinion is on what constitutes a basin and what characteristics of basins to look for. Thanks

[Fish Guide]

The basin of a lake basically begins at the base of the primary shoreline breakline.  Or in other words, where the drop-off levels out and the flat bottom eases out into the lake.  Mille Lacs Lake has a huge basin with multiple humps rising up from it, hope the example helps.

[Lee Borgersen]

Fishin Guide pretty much hit it on the head in regard to the basin on a lake.
 
  Obviously most lake basins will vary in depths from lake to lake. A key factor is locating the basin can at times make a huge difference fishing your success.
 
Most times when you reach the edges of the basin you will find major changes have occurred and taken place in the existing structure. You will find in most cases that the existing STRUCTURE and COVER has gone to a softer bottom and weeds, rocks, and gravel have become very sparse or nonexistent.
 
This edge is called the TRANSITION AREA where you find a substantial continuous change in bottom conditions. At times the transition area will hold some of the largest fish in the lake. Transition areas are used by fish just as the highways are used by us as we travel in our vehicles from point A to point B. This is consider this as a migration route for the fish.
 
In hot weather many fish will hang out over the basin areas for several reasons. They like the comfort zone near the THERMO-CLINE, insect hatches from soft bottom, or baitfish and ciscoes schools. These food sources are most vulnerable when passing across the basin areas due to lack of cover or structure.
 
When fishing deep water reefs and the fish have seemed to move on you it's a good bet they've dropped down to the basin around the same structure. Defiantly spend some time working those transition areas.
 
Always Remember: The fish are either in the deep...The shallow...Or somewhere in between! 
 
SMG