How does my iPhone know where I lived 25 years ago?

Recently when I opened the Maps app, I noticed my VERY old address listed. I haven't lived there since 1989. I know I've not typed that ancient address into the phone, so how is it listed as a suggestion?

Depending on how long you have uses iCloud (Apples cloud storage service) it will store your data across All devices even ones you had ages ago, so if you have typed that address in on an old iPhone 5 years ago then it will still come up because iCloud syncs your data (It can be turned off in Settings -> iCloud)