Every state has some version of Megan’s Law on the books. The original Megan’s Law was enacted 20 years ago in New Jersey and was named for a young girl who was kidnapped, raped, and killed by a neighbor who had a record of prior sex offenses. Other states quickly followed suit.

The laws differ in detail, but generally they require a person convicted of sex crimes to register with a state agency. Information available to the public might include the offender’s name; photograph; address; the date of conviction, incarceration, and release; and the nature of the offense. Various websites even make it possible to enter an address and have a map pop up with the names and locations of registered sex offenders living in the neighborhood