S. 1516 – Cahokia Mounds Mississippian Culture Study Act

AI-Generated Summary

Updated November 24, 2025 at 12:56 AM UTC

The Cahokia Mounds Mississippian Culture Study Act directs the Interior Department to conduct a comprehensive study of three historic mound sites in Illinois—Cahokia, Emerald, and Pulcher. The study will evaluate the sites' national importance, explore the possibility of adding them to the National Park System, and consider other preservation options. Findings and cost estimates must be reported to Congress within three years.

Key Provisions

The Secretary of the Interior must carry out a special resource study of the Cahokia Mounds State Historic Site, Emerald Mounds, and Pulcher Mounds in Illinois.
The study must assess the national significance of these sites and whether they could be added to the National Park System.
It must also look at other ways to preserve, protect, and interpret the sites, including actions by federal, state, local, private, or nonprofit groups.
The Secretary must consult with relevant government agencies, private and nonprofit organizations, and any interested individuals.
The study must include cost estimates for any federal acquisition, development, interpretation, operation, or maintenance of the chosen alternatives.
A final report with findings and recommendations must be submitted to the Senate and House energy and natural resources committees within three years after funding begins.

Legislative Activity

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4 earlier actions

SenateCalendars Latest Action

Placed on Senate Legislative Calendar under General Orders. Calendar No. 478.

July 23, 2026

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SenateIntro Referral

Introduced in Senate

April 29, 2025

SenateIntro Referral

Read twice and referred to the Committee on Energy and Natural Resources. (text: CR S2668)

Energy and Natural Resources Committee

April 29, 2025

SenateCommittee

Committee on Energy and Natural Resources. Ordered to be reported with an amendment in the nature of a substitute favorably.

Energy and Natural Resources Committee

February 4, 2026

SenateCommittee

Committee on Energy and Natural Resources. Reported by Senator Lee with an amendment in the nature of a substitute. Without written report.

Energy and Natural Resources Committee

July 23, 2026

SenateCalendars

Placed on Senate Legislative Calendar under General Orders. Calendar No. 478.

July 23, 2026

Floor Debate

2 members

What members said about S. 1516 on the floor

1 Republican1 Democrat

Sen. John ThuneR-SD · Apr 29, 2025

Mr. President, I ask unanimous consent that the text of the bill be printed in the Record.

Sen. Richard J. DurbinD-IL · Apr 29, 2025

Mr. President, I ask unanimous consent that the text of the bill be printed in the Record.

Sen. Richard J. DurbinD-IL · Apr 29, 2025

Mr. President, I ask unanimous consent that the text of the bill be printed in the Record.

Bill Text

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Reported to SenateIssued July 23, 2026

II

Calendar No. 478

119th CONGRESS

2d Session

S. 1516

IN THE SENATE OF THE UNITED STATES

April 29, 2025

Mr. Durbin (for himself and Ms. Duckworth) introduced the following bill; which was read twice and referred to the Committee on Energy and Natural Resources

July 23, 2026

Reported by Mr. Lee, with an amendment

Strike out all after the enacting clause and insert the part printed in italic

A BILL

To authorize the Secretary of the Interior to conduct a special resource study of the Cahokia Mounds, Emerald Mounds, and Pulcher Mounds in the State of Illinois, and for other purposes.

1.

Short title

This Act may be cited as the Cahokia Mounds Mississippian Culture Study Act.

2.

Findings

Congress finds that—

(1)

the city of Cahokia—

(A)

was inhabited from approximately A.D. 700 to 1400; and

(B)

at its peak from A.D. 1050 to 1200—

(i)

covered nearly 6 square miles; and

(ii)

was home to 10,000 to 20,000 people;

(2)

more than 120 mounds were built over time at the site of the city of Cahokia;

(3)

the site of the city of Cahokia is named for the Cahokia subtribe of the Illinois Confederation, who moved into the area in the 1600s;

(4)

the city of Cahokia was the central hub and largest city of the Mississippian culture that ruled and traded across half of North America, more than 1,250,000 square miles;

(5)

the city of Cahokia—

(A)

was the first known organized urbanization and government north of Mexico; and

(B)

at its peak, was larger than most European cities, including London;

(6)

some of the Cahokia Mounds, which were built from A.D. 900 to 1400, still stand as earthen monuments and remnants of Mississippian culture, which is the greatest prehistoric ancient culture in North America, the people of which are ancestors to many of today’s First People and Nations; and

(7)

the Cahokia Mounds are designated as—

(A)

a National Historic Landmark;

(B)

an Illinois State Historic Site; and

(C)

a United Nations Educational, Scientific, and Cultural Organization World Heritage Site.

3.

Definitions

In this Act:

(1)

Secretary

The term Secretary means the Secretary of the Interior.

(2)

Study area

The term Study Area means—

(A)

the Cahokia Mounds State Historic Site;

(B)

the Emerald Mounds in St. Clair County, Illinois; and

(C)

the Pulcher Mounds in Monroe and St. Clair Counties, Illinois.

4.

Special resource study

(a)

Study

The Secretary shall conduct a special resource study of the Study Area.

(b)

Contents

In conducting the study under subsection (a), the Secretary shall—

(1)

evaluate the national significance of the Study Area;

(2)

determine the suitability and feasibility of designating the Study Area as a unit of the National Park System;

(3)

consider other alternatives for preservation, protection, and interpretation of the Study Area by—

(A)

Federal, State, or local governmental entities; or

(B)

private and nonprofit organizations;

(4)

consult with—

(A)

interested entities of the Federal Government or State or local governmental entities;

(B)

private and nonprofit organizations; or

(C)

any other interested individuals; and

(5)

identify cost estimates for any Federal acquisition, development, interpretation, operation, and maintenance associated with the alternatives considered under paragraph (3).

(c)

Applicable law

The study required under subsection (a) shall be conducted in accordance with section 100507 of title 54, United States Code.

(d)

Report

Not later than 3 years after the date on which funds are first made available to conduct the study required under subsection (a), the Secretary shall submit to the Committee on Energy and Natural Resources of the Senate and the Committee on Natural Resources of the House of Representatives a report containing—

(1)

the results of the study; and

(2)

any conclusions and recommendations of the Secretary.

1.

Short title

This Act may be cited as the Cahokia Mounds Mississippian Culture Study Act.

2.

Definitions

In this Act:

(1)

Indian Tribe

The term Indian Tribe has the meaning given the term Indian tribe in section 102 of the Federally Recognized Indian Tribe List Act of 1994 (25 U.S.C. 5130).

(2)

Secretary

The term Secretary means the Secretary of the Interior.

(3)

Study area

The term Study Area means—

(A)

the Cahokia Mounds State Historic Site;

(B)

the Emerald Mounds in St. Clair County, Illinois; and

(C)

the Pulcher Mounds in Monroe and St. Clair Counties, Illinois.

3.

Special resource study

(a)

Study

The Secretary shall conduct a special resource study of the Study Area.

(b)

Contents

In conducting the study under subsection (a), the Secretary shall—

(1)

evaluate the national significance of the Study Area;

(2)

determine the suitability and feasibility of designating the Study Area as a unit of the National Park System;

(3)

consider other alternatives for preservation, protection, and interpretation of the Study Area by—

(A)

Federal, State, or local governmental entities; or

(B)

private and nonprofit organizations;

(4)

consult with—

(A)

interested entities of the Federal Government or State or local governmental entities;

(B)

applicable Indian Tribes;

(C)

private and nonprofit organizations; or

(D)

any other interested individuals; and

(5)

identify cost estimates for any Federal acquisition, development, interpretation, operation, and maintenance associated with the alternatives considered under paragraph (3).

(c)

Applicable law

The study required under subsection (a) shall be conducted in accordance with section 100507 of title 54, United States Code.

(d)

Report

Not later than 3 years after the date on which funds are first made available to conduct the study required under subsection (a), the Secretary shall submit to the Committee on Energy and Natural Resources of the Senate and the Committee on Natural Resources of the House of Representatives a report containing—

(1)

the results of the study; and

(2)

any conclusions and recommendations of the Secretary.

July 23, 2026

Reported with an amendment