Please note: As of 4/17/22 the site is under development.
| City | Companies | |
| 1 | Algona | Garfield, Richardson, & Company North American Gas Engine Works |
| 2 | Altoona | Altoona Manufacturing Company |
| 3 | Atkins | Wendel, Jacob C. |
| 4 | Aurora | Aurora Manufacturing Company |
| 5 | Bellevue | Iowa Marine Engine & Launch Works |
| 6 | Bloomfield | Bruce, Albert W. |
| 7 | Burlington | Criner, Harry J. Murray Iron Works |
| 8 | Cedar Falls | Clay-Christie Company Yale Gas Engine Company |
| 9 | Cedar Rapids | Brown-Loftus Company Cedar Rapids Foundry & Machine Company Perfection Gas Engine Company Scott, Charles A. |
| 10 | Chariton | Eureka Manufacturing Company |
| 11 | Charles City | American Engine & Tractor Company Charles City Engine Service Hart-Parr Company |
| 12 | Cherokee | Cherokee Manufaturing Company |
| 13 | Clinton | Climax Engineering Company Clinton Motorcycle & Power Company Clinton Novelty Iron Works Clinton Separator & Engine Company Collis Company Iowa Machine Works Lamb Boat & Engine Company Walker, H. E. |
| 14 | Council Bluffs | Walker Manufacturing Company |
| 15 | Davenport | Anderson Automatic Engine Company Buck, J. W. Davenport Ice Chipping Machine Company Davenport Machine & Foundry Company Davenport Manufacturing Company Davenport Motor Company East Davenport Machine & Novelty Company Ideal Lighting Company Implement Manufacturing Company Schmidt Brothers Company, Engine Works Sebelin Machine & Tool Works Stroben, John F. Warnerlite Company White Lily Washer Company |
| 16 | Des Moines | Chambers & Company, G. S. Des Moines City Gas Engine Works Des Moines Gas Engine & Electric Company Diamond Engine Company Dodd Motor Company Gibbons Machine & Foundry Company Globe Machinery & Supply Company Hume, J. T. Monarch Machine Company Purinton Manufacturing Company S.P.C. Gas Engine Company Wilson Machine Company |
| 17 | Dubuque | Adams Company Dubuque Gasoline Engine Company Eska Mo Company Novelty Iron Works Scheppele Machine Works |
| 18 | Dyersville | Dyersville Gasoline Engine Company |
| 19 | Essex | Porter, W. F. |
| 20 | Fairfield | Fairfield Gas Engine Company |
| 21 | Ft. Dodge | Baker Manufacturing Company Hickey, Henry J. Iowa Foundry & Manufacturing Company |
| 22 | Ft. Madison | Ft. Madison Gas Engine Company Keystone Iron Works |
| 23 | Froehlich | Froehlich, John |
| 24 | Grinnell | Dodge Tool Company |
| 25 | Hampton | Hampton Foundry & Machine Company |
| 26 | Harlan | Nelson Gas Engine & Automobile Company |
| 27 | Independence | Enterprise Engine Company Ideal Gas Engine Company Sherman & Smith Manufacturing Company |
| 28 | Iowa City | Kelly Western Manufacturing Company, O.S. |
| 29 | Iowa Falls | Gade Brothers Manufacturing Company |
| 30 | Jefferson | Jefferson Gas Engine Company North & Company, L.C. Western Tool |
| 31 | Keokuk | Kollmyer & Talbot |
| 32 | Knowlton | Ideal Farm Implement Company |
| 33 | La Porte City | Fox & Sons, J.W. |
| 34 | La Mars | Crawford, J. B. |
| 35 | Lone Tree | Monarch Grubber Company |
| 36 | Lyons | Pelton & Sons, T.G. |
| 37 | Maquoketa | Clinton Machine Company Maquoketa Iron Works |
| 38 | Marshalltown | Ketchum & Company Lennox Machine Company O.K. Gas Engine Company Shorthill Company, A.E. |
| 39 | Mason City | Chase Gas Engine Company |
| 40 | Muscatine | Adams-McCoy Electric Company Muscatine Motor Company Stohr & Freund |
| 41 | New Hampton | New Hampton Manufacturing Company Stickley-Hunter Gasoline Engine Company |
| 42 | Newton | Maytag Company One Minute Manufacturing Company Parsons Band Cutter & Self Feeder Company Parsons-Hawkeye Company |
| 43 | Oelwein | Independent Light & Power Company Potter, Valda W. |
| 44 | Ottumwa | Baker, Jackson H. Moline Engine & Pump Company Ottumwa-Moline Engine & Pump Company |
| 45 | Perry | Globe Manufacturing Company |
| 46 | Sioux Center | Wandscheer Brothers |
| 47 | Sioux City | Sioux City Cement Machinery Company Sioux City Engine & Machinery Company Stickley-Hunter Gasoline Engine Company |
| 48 | Stanley | Smith, Irvine |
| 49 | Tama | Hawkeye Manufacturing Company |
| 50 | Waterloo | Armstrong Manufacturing Company Armstrong-Quam Manufacturing Company Associated Manufacturers Caldwell-Hollowell Company Cascaden Manufacturing Company Cascaden-Vaughn Company Cement Tile Machinery Company Chamberlain Machine Works Corn Belt Motors Company Davis Gasoline Engine Company Davis Gasoline Engine Works Empire Novelty Company Faultless Gasoline Engine Company Ferguson Manufacturing Company Galloway & Company, William Galloway Company Galloway Company, William Goodman, W.A. Huron Steel & Iron Manufacturing Company Interstate Tractor Company Iowa Dairy Separator Company Iowa Gasoline Engine Company Iowa Spreader & Engine Company Litchfield Manufacturing Company Miller & Son, George B. Miller Company, George B. National Engine Company Sandy McManus Incorporated Sheldon Engine & Sales Company Summitt Carriage – Mobile Company Waterloo Foundry Company Waterloo Gasoline Engine Company Waterloo Motor Works Webster Engine Works Western Harness & Supply Company |
| 51 | Webster City | Smisor Brothers |
| 52 | West Union | Crabb Gas Engine Company |
Sources: Gas Engine Trademarks (by C.H. Wendel), and Personal Collection/Research