How to Find Fish Using Lake Structure

Ask any professional bass angler what separates tournament winners from the rest of the field and the answer is almost always the same: they find the right structure. Structure — the physical shape of the lake bottom — dictates where fish live, feed, and travel. If you understand structure, you understand where the fish are.

The good news? You don't need a $100,000 bass boat with cutting-edge electronics to read structure. A free lake depth map and some basic knowledge will put you on fish-holding structure faster than the guy who's been fishing the same bank for twenty years.

Structure vs. Cover: Know the Difference

Before we dive in, let's clear up a common confusion. Structure and cover are not the same thing.

• Structure = the shape of the lake bottom. Points, drop-offs, humps, channels, flats, ledges. This is permanent — it doesn't move.
• Cover = objects on or near the bottom. Fallen trees, brush piles, docks, rocks, weed beds. Cover can change or be removed.

Fish relate to both, but structure is the foundation. Cover on good structure is the ultimate fish magnet. A brush pile sitting on a flat with no nearby depth change might hold a few fish. That same brush pile sitting on a point next to a creek channel? That's where the money is.

The 6 Key Structures That Hold Fish

1. Points

A point is any piece of bottom that extends from the shore (or from shallow water) into deeper water. On a depth map, points appear as contour lines that push outward toward the middle of the lake.

Points are fish highways. Bass, walleye, crappie — they all use points to travel between shallow feeding areas and deep resting zones. The tip of a point where it meets deeper water is almost always a high-percentage spot.

There are two types to know:

• Main lake points — large points on the main body of the lake. These are obvious and get heavy fishing pressure, but they still produce, especially for offshore fish in summer.
• Secondary points — smaller points inside creek arms or along shoreline pockets. These get far less pressure and are often better for bass, especially during pre-spawn when fish are staging.

2. Drop-Offs and Ledges

A drop-off is a rapid depth change — the bottom goes from shallow to deep quickly. On a depth map, this appears as tightly compressed contour lines. A ledge is similar but usually refers to a more pronounced horizontal shelf before the drop.

Drop-offs are ambush zones. Predator fish sit in the deeper water and dart up to the shallow edge to attack baitfish. The steeper and more defined the drop-off, the more fish it typically holds. Ledge fishing in summer is arguably the most productive pattern in all of bass fishing — it won the Bassmaster Classic multiple times.

Look for drop-offs that:

• Run parallel to a creek channel
• Have cover (stumps, rocks, brush) along the edge
• Transition from a flat to deep water (the "break line")

3. Humps and Underwater Islands

A hump is a high spot on the lake bottom surrounded by deeper water — an underwater hill. On a depth map, humps appear as concentric circles of decreasing depth. These are offshore fish magnets because they concentrate baitfish and give predators a defined area to hunt.

The best humps:

• Top out at 8-15 feet with 25+ feet of water around them
• Have irregular shapes (not perfectly round) creating multiple edges
• Are near a creek channel, which provides a deep-water highway for fish to access the hump

A single productive hump can hold fish all year long. In summer, bass school up on humps and feed on shad — and most bank-beaters never even know the hump exists because they can't see it from the surface.

4. Creek Channels

Every reservoir has them — the original creek and river beds that were flooded when the dam was built. Creek channels are the single most important structural feature on most reservoirs because they serve as highways, holding areas, and feeding zones simultaneously.

On a depth map, creek channels appear as curving lines of deeper water running through the lake. Key areas along a channel include:

• Channel bends — where the channel curves, it creates a point on the inside and a deeper hole on the outside. Both hold fish.
• Channel swings near shore — where the old creek bed swings close to the bank, fish can move from deep to shallow quickly. These are pre-spawn staging gold.
• Channel intersections — where two creek channels merge, you get a concentration of structure and current. These spots are magnets for catfish, walleye, and bass.

5. Flats

A flat is a large area of relatively uniform depth — the contour lines are widely spaced. Flats might seem boring on a map, but they're critical feeding areas, especially at certain times of year.

Shallow flats (2-8 feet) adjacent to deeper water are prime spawning habitat in spring. Deeper flats (12-25 feet) hold schools of baitfish in summer and are prime spots for crappie and bass.

The key with flats is finding something different. A flat with one small depth change — a single rock pile, a slight depression, or a lone stump — will concentrate every fish on that entire flat. That subtle 1-foot depth change you see on a detailed map? That's often the sweet spot.

6. Saddles

A saddle is a shallow ridge connecting two deeper areas — like an underwater bridge between two humps, or a shallow connection between two points. Fish use saddles to travel between structural elements, and they often pause on saddles to feed.

Saddles are hard to find without a depth map, which means they're almost always unpressured. On a map, look for two areas of deeper water (close contour lines) connected by a shallower strip. That strip is your saddle — and it's probably loaded with fish that nobody else is targeting.

How to Read Structure on a Depth Map

Now that you know what to look for, here's a practical step-by-step for reading structure off a lake depth map:

1. Find the creek channel first. It's the backbone of the lake. Everything relates to it. Mark where it runs and note every bend, intersection, and place it swings near shore.
2. Identify major points. Look for contour lines extending into deeper water from the shoreline. Prioritize points that intersect or are adjacent to the creek channel.
3. Locate drop-offs. Find where contour lines compress — that's your break line. Trace it around the lake and note where it has cover-holding features (rocky banks, timber areas).
4. Spot humps and saddles. Look for closed circles (humps) and shallow connections between deeper areas (saddles). These are your secret weapons.
5. Mark flats with adjacent deep water. A flat by itself isn't special. A flat next to a 20-foot drop-off with a channel running behind it? That's a fish-holding machine.

Matching Structure to Seasons

• Spring (Pre-Spawn): Secondary points, channel swings near shore, flats adjacent to deep water. Fish are moving shallow. See our spring bass guide →
• Summer: Offshore humps, main lake ledges, deep points, channel bends. Fish go deep to escape heat.
• Fall: Creek arm points, channel intersections, shallow flats in the backs of creeks. Fish follow baitfish toward the shallows.
• Winter: Deepest structure near the main channel. Steep bluffs, deep points, primary channel bends. Fish group up and go slow.

The Compound Effect

The best fishing spots on any lake are where multiple structural elements converge. A point by itself is good. A point that intersects a creek channel with a brush pile on the edge adjacent to a flat? That's four features in one spot — and it will hold fish year-round in some capacity.

Every time you study a depth map, you're building a mental database of structure that carries forward to every lake you ever fish. The patterns are universal — the same type of point that holds fish on an Indiana reservoir holds fish on a Texas impoundment or a Tennessee Valley lake. Learn to read structure once, and you can fish anywhere.