- Agriculture 17
- Architecture 172
- Art and Design 25
- Aviation 7
- Biography 76
- Bridges 13
- Businesses 66
- Cemeteries 17
- Civic Organizations 65
- Conflict 25
- Crime 15
- Disasters 9
- Early Settlers & Settlement 27
- Economy 6
- Education 71
- Entertainment 74
- Entrepreneurs 31
- Environment 57
- Events 26
- Food 42
- Government and Politics 33
- Great Depression 11
- Healthcare 25
- Immigration 66
- Industry 67
- Inventors 7
- Labor 14
- Libraries 18
- Museums 37
- Music 23
- Neighborhoods and Districts 66
- Parks 42
- Protest 5
- Public Art 12
- Public Housing 4
- Race and Ethnicity 123
- Recreation 26
- Religion 88
- Rock and Roll 10
- Science 6
- Sexuality and Gender 9
- Sports 25
- Suburbs 79
- Technology 13
- Transportation 39
- Urban Planning and Design 35
- Wartime 21