Some were misdemeanors, but most were felonies, serious crimes according to criminal law, resulting in lengthy prison sentences. In some states, it was the same penalty for having sex with your date and killing him.
During the 1970s many sodomy laws were repealed. Some states added new laws that applied only to gay people, such as "homosexual conduct" in Texas.
During the 1980s and 1990s, more sodomy laws were invalidated through court cases.
But it was still illegal to engage in same sex acts in 16 states in 2003, when the Supreme Court case of Lawrence v. Texas invalidated all sodomy laws in the U.S.
That was only 12 years ago, so many gay people over age 30 have committed multiple felonies in the U.S.
Here are the states where I engaged in acts that could be prosecuted as felonies:
When I was in graduate school at Indiana University in 1983, Viju and I drove down to Kentucky for a concert in Louisville, and spent the night.
Sodomy, buggery, or bestiality. 2-5 years. Invalidated in 1992
2. Texas
I lived in Texas for about nine months while teaching at Hell-fer-Sartain State University (1984-85).
Homosexual conduct. 2 to 15 years. It was reduced to a misdemeanor in 1993, and invalidated in 2003.
3. Nevada
When I was living in West Hollywood, we drove into Las Vegas to go to the casinos about three times.
The crime against nature. 1 year to life. Repealed in 1993.
I spent a semester studying Biblical Hebrew at Vanderbilt University (1990).
The notorious crime against nature. 5 to 15 years. Invalidated in 1996.
I don't remember why we went to Atlanta, but I remember being confused by a dozen streets named Peachtree.
Any act involving the sex organs of one person and the mouth or anus of another. 1-20 years. Repealed in 1995.
6. District of Columbia.
One of my favorite cities in North America. Flew out twice in the early 1990s.
Placing his or her sex organs in the mouth or anus of another. 10 years. Repealed in 1995.
7. Virginia
I visited friends in Norfolk for a week in 1996. Probably went to DC, too.
The crime against nature. 2-5 years. Invalidated in 2003.
They took me down to a resort on the coast of North Carolina.
The crime against nature with mankind or beast. 3-5 years. Invalidated in 2003.
9. Montana.
We drove cross-country in 1995 to visit Rock Island, and passed through a number of felony states on the way back, including South Dakota, Montana, Wyoming, and Idaho. Fortunately, we only spent the night in Montana.
Deviant sexual relations. 10 years to life. Invalidated in 1997.
10. South Carolina.
On the way from New York to Florida in 2001, I spent the night in South Carolina.
Buggery. 5 years. Invalidated in 2003.