Nonprofit · EIN 46-0337824
MAMMOTH SITE OF HOT SPRINGS SOUTH DAKOTA INC
Tax-exempt · HOT SPRINGS, SD 57747
Financials
| Year ended | Form | Revenue | Expenses | Net income | Total assets | Liabilities | Net assets |
|---|---|---|---|---|---|---|---|
| October 31, 2025 | 990 | $1,618,504 | $1,684,158 | -$65,654 | $6,458,752 | $60,437 | $6,398,315 |
| October 31, 2023 | 990 | $1,828,957 | $1,809,928 | $19,029 | $5,979,441 | $65,050 | $5,914,391 |
Financial details: 990 for the year ended October 31, 2025
Revenue
- Contributions, gifts and grants
- $175,869
- Program service revenue
- $1,089,217
- Investment income
- $67,851
- Net gain from sales of assets
- $3,818
- Net income from sales of inventory
- $285,567
- Other revenue
- $285,567
Expenses
- Grants and similar amounts paid
- $0
- Other salaries and wages
- $840,744
- Salaries, compensation and benefits (total)
- $949,899
- Professional fundraising fees
- $0
- Occupancy
- $144,858
- Travel
- $14,794
- Depreciation
- $204,924
- Program services (functional)
- $1,323,851
- Management and general (functional)
- $260,992
- Fundraising (functional)
- $99,315
Balance sheet and other
- Total assets, start of year
- $6,358,764
- Total assets, end of year
- $6,458,752
- Total liabilities, end of year
- $60,437
- Net assets, end of year
- $6,398,315
- Land, buildings and equipment
- $2,705,422
- Publicly traded securities
- $1,995,726
- Net assets without donor restrictions
- $6,363,326
- Net assets with donor restrictions
- $34,989
- Gross receipts
- $1,855,678
- Employees
- 54
- Volunteers
- 100
- Year formed
- 1975
- State of legal domicile
- SD
From the e-filed returns the IRS publishes as XML (latest three processing years; amended returns replace the original). PDF copies at the IRS.
Officers, directors and key employees
As listed on the 990 for the year ended October 31, 2025, highest compensation first.
| Name | Title | Hours / week | Compensation |
|---|---|---|---|
| CALEB ARCENEAUX | SECRETARY Trustee or director, Officer | 1 | $0 |
| TIA BERENS | MEMBER Trustee or director | 1 | $0 |
| RICK DENHERDER | MEMBER Trustee or director | 1 | $0 |
| JANE FARRELL | LEGAL ADVISO Trustee or director | 1 | $0 |
| GREG GUNWALL | MEMBER Trustee or director | 1 | $0 |
| TERRY HINN | VICE PRESIDE Trustee or director, Officer | 1 | $0 |
| DR MIKE LEITE | MEMBER Trustee or director | 1 | $0 |
| ANNA MERRILL | MEMBER Trustee or director | 1 | $0 |
| JOHN PENCE | PRESIDENT Trustee or director, Officer | 1 | $0 |
| ROBERT PREUSS | TREASURER Trustee or director, Officer | 1 | $0 |
| RANDY SCHUR | MEMBER Trustee or director | 1 | $0 |
| AMY SPEARS | MEMBER Trustee or director | 1 | $0 |
990 for the year ended October 31, 2023: 12 people
| Name | Title | Hours / week | Compensation |
|---|---|---|---|
| CALEB ARCENEAUX | SECRETARY Trustee or director, Officer | 1 | $0 |
| RICK DEHERDER | MEMBER Trustee or director | 1 | $0 |
| JANE FARRELL | LEGAL ADVISO Trustee or director | 1 | $0 |
| DR RICH GROSS | VICE PRESIDE Trustee or director, Officer | 1 | $0 |
| GREG GUNWALL | MEMBER Trustee or director | 1 | $0 |
| DR MIKE LEITE | MEMBER Trustee or director | 1 | $0 |
| HEIDI MCBRIDE | MEMBER Trustee or director | 1 | $0 |
| ANNA MERRILL | MEMBER Trustee or director | 1 | $0 |
| JOHN PENCE | PRESIDENT Trustee or director, Officer | 1 | $0 |
| ROBERT PREUSS | TREASURER Trustee or director, Officer | 1 | $0 |
| RANDY SCHUR | MEMBER Trustee or director | 1 | $0 |
| AMY SPEARS | MEMBER Trustee or director | 1 | $0 |
Address and contacts
- Address (IRS master file)
- 1800 HIGHWAY 18 BYP, HOT SPRINGS, SD 57747-9604
- Principal officer (990 for 2024)
- JOHN PENCE, PO BOX 692, HOT SPRINGS, SD 57747
- Signed the 990
- ROBERT PREUSS, TREASURER
- Phone
- (605) 745-6017
- Website
- WWW.MAMMOTHSITE.COM
- Return prepared by
- DESMET CPA GROUP LLC
Mission
THE MISSION OF THE ORGANIZATION IS THE PRESERVATION, RESEARCH, AND INTERPRETATION OF THE MAMMOTH SITE OF HOT SPRINGS, SOUTH DAKOTA, AND DEVELOPMENT OF A BROAD UNDERSTANDING OF THE LATE ICE AGE RECORD ACROSS A GLOBAL FRAMEWORK.
Program accomplishments
- RECOVER, PRESERVE AND EXHIBIT FINDINGS FROM THE MAMMOTH SITE. PROVIDE EDUCATIONAL PROGRAMS AND GUIDED TOURS OF THE SITE AND BONEBED.Expenses $1,323,851 · revenue $1,089,217
What it must file and when
IRS records say it files Form 990 or 990-EZ. Based on its last return; a smaller organization may file the 990-N. Its accounting year ends in October, so each return is due on the 15th day of the 5th month after that.
| Tax year | Year ended | Due | IRS public records |
|---|---|---|---|
| 2025 | October 31, 2026 | March 15, 2027 | Not due yet |
| 2024 | October 31, 2025 | March 16, 2026 | 990 on file |
| 2023 | October 31, 2024 | March 17, 2025 | Check at the IRS |
IRS record
- EIN
- 46-0337824
- Tax-exempt status
- 501(c)(3): Charitable, religious, educational or scientific organization
- Foundation status
- Publicly supported organization (170(b)(1)(A)(vi))
- Donations deductible (Pub 78)
- Public charity, 50% deduction limit
- Exempt since
- 1977
- Accounting year ends
- October
- Files
- Form 990 or 990-EZ
- Category (NTEE)
- Arts, culture and humanities (A560)
- Assets (IRS master file)
- $6,458,752
- Income (IRS master file)
- $1,855,678
Filing history
| Form | Year ended | Revenue | Expenses | Assets | Return |
|---|---|---|---|---|---|
| 990 | October 2025 | $1,618,504 | $1,684,158 | $6,458,752 | XML |
| 990 | October 2023 | $1,828,957 | $1,809,928 | $5,979,441 | XML |
| 990 | October 2022 | $1,811,077 | $1,852,547 | $5,897,905 | IRS |
| 990 | October 2021 | – | – | – | IRS |
| 990 | October 2020 | – | – | – | IRS |
| 990 | October 2019 | – | – | – | IRS |
| 990 | October 2018 | – | – | – | IRS |
990-N: the IRS bulk file holds only the latest e-Postcard per organization; earlier years come from archived copies of that file since 2020 and can have gaps (the IRS e-Postcard search lists every one). 990, 990-EZ, 990-PF, 990-T: every e-filed return in the IRS e-file index since 2019; XML for the latest three processing years, amounts from the IRS Statistics of Income extracts before that. PDF copies and determination letters at the IRS (search EIN 46-0337824).
Questions about MAMMOTH SITE OF HOT SPRINGS SOUTH DAKOTA INC
- What is the EIN of MAMMOTH SITE OF HOT SPRINGS SOUTH DAKOTA INC?
- The employer identification number (EIN) of MAMMOTH SITE OF HOT SPRINGS SOUTH DAKOTA INC is 46-0337824.
- Is MAMMOTH SITE OF HOT SPRINGS SOUTH DAKOTA INC tax-exempt?
- Yes. The IRS lists it as tax-exempt under section 501(c)(3) since 1977.
- Are donations to MAMMOTH SITE OF HOT SPRINGS SOUTH DAKOTA INC tax-deductible?
- Yes. It is listed in IRS Publication 78 (Public charity, 50% deduction limit).
- Which annual return does MAMMOTH SITE OF HOT SPRINGS SOUTH DAKOTA INC file?
- Form 990 or 990-EZ. Based on its last return; a smaller organization may file the 990-N.
- When is the next return of MAMMOTH SITE OF HOT SPRINGS SOUTH DAKOTA INC due?
- The return for tax year 2025 (the year ending October 31, 2026) is due March 15, 2027. Form 8868 extends it by six months; the 990-N cannot be extended.
- When did MAMMOTH SITE OF HOT SPRINGS SOUTH DAKOTA INC last file with the IRS?
- The latest return in the IRS public files is the 990 for the year ended October 2025.
- Who is the principal officer of MAMMOTH SITE OF HOT SPRINGS SOUTH DAKOTA INC?
- The 990 for the year ended October 31, 2025 names JOHN PENCE.
- Who are the officers and directors of MAMMOTH SITE OF HOT SPRINGS SOUTH DAKOTA INC?
- The 990 for the year ended October 31, 2025 lists 12 people; 0 received compensation from the organization.
- How much revenue does MAMMOTH SITE OF HOT SPRINGS SOUTH DAKOTA INC have?
- On its 990 for the year ended October 31, 2025 it reported revenue of $1,618,504, expenses of $1,684,158 and total assets of $6,458,752 at year end.
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- INSTITUTE OF RANGE & THE AMERICAN MUSTANG EIN 46-0401462 · last filed 990 for 2025
- HOT SPRINGS AMBULANCE SERVICE INC EIN 46-0417845 · last filed 990 for 2025
- BLACK HILLS PARKS AND FORESTS ASSOCIATION EIN 46-6017180 · last filed 990 for 2025
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All nonprofits in HOT SPRINGS · South Dakota · Arts, culture and humanities