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| Academic Magnet High School | C | 2 | South Carolina | Charleston County | SC | |
| Adlai E Stevenson HS | C | 2 | Division C Regional | Lincolnshire District 125 | IL | |
| Archimedean Upper Conservatory | C | 3 | Southeast Regional at Florida Atlantic University | Miami-Dade | FL | |
| Bayard Rustin High School | C | 2 | Mini Satellite Hybrid SO Regional | West Chester | PA | |
| BHS SciOly | C | | HSSO 2021 PRACTICE Regional | WCS | TN | |
| Bismarck High School | C | 1 | | Bismarck Public Schools | ND | |
| Blue Valley West High School | C | 2 | NE KS Satellite SO Regional | Blue District USD 229 | KS |
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| Bridgeland High School | C | 1 | University of Texas Regional | Cypress-Fairbanks ISD | TX | |
| Brooklyn Technical HS | C | 2 | | New York City Public Schools | NY | |
| Camas High | C | 1 | Southwest Washington | Camas School District | WA |
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| Canyon High School | C | 2 | SoCal Joint Regional | Orange Unified | CA |
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| Cary Academy- Upper School | C | 3 | | independent | NC | |
| Cedar Ridge High School | C | 2 | | Orange County Schools | NC | |
| Cedar Springs Homeschool C Division | C | 1 | | Knox County | TN |
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| Centennial High School | C | 1 | Eastern Maryland Region; Div. C | HCPSS | MD | |
| Cerritos High School | C | 2 | | ABC Unified School District | CA | |
| Chapel Hill High School | C | 3 | | Chapel Hill Carrboro City School | NC | |
| Charlotte Catholic High School | C | 2 | | Mecklenburg Area Catholic Schools | NC | |
| Chattahoochee High School | C | 2 | | Fulton County | GA |
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| Clinton Senior High School | C | 2 | | Clinton | NY | |
| Columbia High School | C | 2 | Capital Region | East Greenbush Central School District | NY | |
| Cypress Springs High School | C | 1 | Gulf Coast Regional | CFISD | TX | |
| D. H. Conley High School | C | 1 | | Pitt County Schools | NC |
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| Davis Senior High School | C | 2 | Sacramento Regional Science Olympiad | Davis Joint Unified School District | CA | |
| Division Avenue High School | C | 3 | | Levittown Public Schools | NY | |
| Durham Academy Upper School | C | 2 | | Independent School | NC | |
| Eastview High School | C | 2 | Eastview | Independent School District 196 | MN | |
| Ed W. Clark High School | C | 1 | State Competition | Clark County School District | NV |
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| Etiwanda High School | C | 2 | SoCal Joint Regional | Chaffey Joint Union High School District | CA | |
| Fairfax High School | C | 2 | | Fairfax County Public Schools | VA | |
| Farragut High School | C | 2 | | Knox County Schools | TN | |
| Fayetteville-Manlius Senior High School | C | 2 | New York MidState | Fayetteville-Manlius Central School District | NY |
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| Freedom High School | C | 1 | | Loudoun County Public Schools | VA | |
| Garnet Valley High School | C | 1 | Mini Satellite Hybrid SO Regional | Garnet Valley School District | PA | |
| General Douglas MacArthur High School | C | 1 | | Levittown Public Schools | NY | |
| Glen A. Wilson High School | C | 2 | | Hacienda La Puente Unified | CA | |
| Great Oak High School | C | 3 | | Temecula Valley USD | CA |
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| Harvard-Westlake School | C | 1 | Los Angeles - South | Independent | CA | |
| Hillsborough HS | C | 1 | | Hillsborough Township School District | NJ | |
| Homeschool Science Colorado | C | 1 | Colorado All-Regional | Homeschool | CO |
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| Iolani School | C | 3 | HSSO Div C Honolulu & Windward | Oahu | HI | |
| Isaac Bear Early College | C | 3 | | New Hanover County | NC | |
| John P. Stevens High School | C | 2 | | Edison Township Public Schools | NJ |
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| John T Hoggard High School | C | 2 | | New Hanover | NC |
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| Larchmont Charter School | C | 1 | Los Angeles | Los Angeles Unified | CA | |
| Lower Merion High School | C | 1 | Mini Satellite Hybrid SO Regional | Lower Merion School District | PA | |
| Middle Creek High School | C | 2 | | Wake County PS | NC | |
| Mt. Hebron HS | C | | Eastern Maryland Region; Div. C | Howard County | MD | |
| New Trier High School | C | 3 | Division C Regional | New Trier Township High School District 203 | IL | |
| NewTestAlex | C | 1 | | testdistrict | NC | |
| North Carolina School of Science and Mathematics | C | 2 | | University of North Carolina | NC | |
| North Hollywood High School | C | 2 | Los Angeles - South | Los Angeles Unified School District | CA | |
| Northville High School | C | 1 | | Northville | MI |
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| Northwestern Lehigh High School | C | 2 | Mini Satellite Hybrid SO Regional | Northwestern Lehigh School District | PA |
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| Olympia High School | C | 3 | Satellite SO (Virtual) | Orange County Public Schools | FL | |
| Orlando Science High School | C | | Satellite SO (Virtual) | Orange | FL | |
| Parkland High School | C | 2 | Mini Satellite Hybrid SO Regional | Parkland School District | PA | |
| Plattsburgh High School | C | 3 | Adirondack | Plattsburgh High School | NY | |
| Portola High School | C | 2 | SoCal Joint Regional | Irvine Unified School District | CA |
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| Prestonwood Christian Academy | C | 1 | Corpus Christi Regional Science Olympiad | Plano/ private | TX | |
| Princeton Day School (HS) | C | 2 | | Private | NJ | |
| Princeton HS | C | | | Princeton Public Schools | NJ |
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| Raleigh Charter High School | C | 3 | National Ready Tournament | Charter | NC | |
| Reservoir HS | C | 2 | Eastern Maryland Region; Div. C | Howard County | MD | |
| Robinson Secondary | C | 3 | Second VA Regional (2/6) | Fairfax County Public Schools | VA |
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| Rock Bridge High School | C | 2 | Region 5 B/C | Columbia Public Schools | MO | |
| Sharon High School | C | 1 | | Sharon Public Schools | MA | |
| Simon G. Atkins Academic and Technology High School | C | 1 | | Winston Salem/Forsyth County Schools | NC | |
| Solon High School | C | 1 | Northeast Ohio Regional Tournament | Solon City Schools | OH | |
| South County High School | C | 3 | | Fairfax County Public Schools | VA | |
| South Forsyth High School | C | 3 | Georgia | Forsyth County | GA | |
| South High Community School | C | 1 | MA 1 | South Worcester | MA | |
| South Pasadena High School | C | 1 | Los Angeles - South | South Pasadena Unified School District | CA | |
| Staten Island Technical High School | C | 3 | New York City East | District 31 | NY | |
| Stevenson High School | C | 1 | MI Regional 7 | Utica Community Schools | MI | |
| Strath Haven High School | C | 1 | Mini Satellite Hybrid SO Regional | Wallingford Swarthmore SD | PA | |
| Syosset HS | C | 1 | western Long Island | Syosset | NY | |
| Torrey Pines High School | C | 1 | SoCal Joint Regional | San Dieguito Union High School District | CA |
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| Triangle Math and Science Academy | C | 2 | Southern Wake Tournament. | Wake County | NC | |
| Union County Vocational and Technical Schools HS | C | 1 | | Union County Vocational Technical Schools | NJ |
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| Vernon Hills High School | C | 2 | Division C Regional | Community High School District 128 | IL | |
| Wake Early College of Health & Sciences | C | 2 | | Wake County | NC | |
| Westborough High School | C | 2 | MA 1 | Westborough Public Schools | MA | |
| Westlake High School | C | 2 | Northeast Ohio Regional Tournament | Westlake City Schools | OH |
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| William G. Enloe High School | C | 2 | North Carolina | Wake County | NC | |