Lake Petersburg Dam

TRIB SANGAMON RIVER· Menard, Illinois· Built 1961· Earth· 85 ft tall
High Hazard Recreation Private

Key Takeaway

Lake Petersburg Dam is classified as high hazard in Illinois. It was completed in 1961 and is 65 years old. Its primary use is recreation. High hazard means loss of life is likely if the dam fails — it does not indicate the dam's current condition. Learn more.

Physical Details

Dam Height 85 ft (taller than 98.7% in IL)
Dam Length1,300 ft
Dam TypeEarth
Max Storage6.7K acre-ft
Normal Storage4.3K acre-ft
Max Discharge1,985 cfs
Year Completed1961 (65 years old)
NID IDIL00518

Safety Information

High Hazard

Loss of human life is likely if the dam fails.

Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?

Emergency Action Plan: Yes
Last Inspection: September 24, 2020
State Regulated: Yes
Regulatory Agency: IDNR

Ownership

LAKE PETERSBURG ASSOCIATION

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Lake Petersburg Dam?

Lake Petersburg Dam is classified as High Hazard. Loss of human life is likely if the dam fails. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Lake Petersburg Dam?

Lake Petersburg Dam is owned by LAKE PETERSBURG ASSOCIATION (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Lake Petersburg Dam built?

Lake Petersburg Dam was completed in 1961, making it 65 years old. Many U.S. dams were built between the 1930s and 1970s during a period of major infrastructure investment.

What is the primary purpose of Lake Petersburg Dam?

Lake Petersburg Dam serves the following purposes: Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Lake Petersburg Dam?

Lake Petersburg Dam has a dam height of 85 ft. Dam height is measured from the natural streambed at the downstream toe to the top of the dam, and may differ from the visible height.

When was Lake Petersburg Dam last inspected?

Lake Petersburg Dam was last inspected on September 24, 2020. Inspection dates indicate when a formal review occurred, not the results of that inspection.

Data from the National Inventory of Dams (NID) maintained by the US Army Corps of Engineers. Dam conditions may have changed since the last update. This site is not affiliated with USACE. Do not use for emergency planning — contact your local dam safety program.