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Boating Basics

U.S. Aids to Navigation System (ATON)

Buoys and markers are the “traffic signals” that guide vessel operators safely along some waterways. They also identify dangerous or controlled areas and give directions and information. As a recreational boat or PWC operator, you will need to know the lateral navigation markers and non-lateral markers of the U.S. Aids to Navigation System.

Lateral Markers

These navigation aids mark the edges of safe water areas; for example, directing travel within a channel. The markers use a combination of colors and numbers, which may appear on either buoys or permanently placed markers.

Red Right Returning is a reminder of the correct course when returning from open waters or heading upstream.

Red Right Returning boat enters a channel

Non-Lateral Markers

Non-lateral markers are navigational aids that give information other than the edges of safe water areas. The most common are regulatory markers which are white and use orange markings and black lettering. These markers are found on the lakes and rivers of Missouri.


Squares indicate where to find food, supplies, repairs, etc. and give directions and other information.


Circles indicate a controlled area such as speed limit, no fishing or anchoring, ski only or no skiing, or “slow, no wake.”

Prohibited (Boats Keep Out)

Crossed diamonds indicate areas off-limits to all vessels such as swimming areas, dams, and spillways.


Diamonds warn of dangers such as rocks, shoals, construction, dams, or stumps. Always proceed with caution.

Information, controlled, exclusion, and danger non-lateral markers
Information, controlled, prohibited, and danger non-lateral markers