The mailbox is actually part of the house, but… this.
No. You own it, unless it’s one of those neighborhood cluster boxes they make people use in newly-built developments.
They have jurisdiction because that’s what the law is. Mailboxes are for mail on which postage has been paid, period. You can have another box for things like newspapers, though.
The post office also has a legal monopoly on all letters. UPS and FedEx are prohibited from delivering envelopes and the like unless they charge a much higher amount (currently several dollars).
All mailboxes. (The single boxes on posts by the road are not owned by the post office.)
As noted, you own the box itself but the USPS controls it. That is not a technicality either. You can get into a metric shit-ton of trouble for screwing with other people’s mailboxes. That includes putting unauthorized stuff in them or vandalizing them.
“Mailbox baseball” (hitting mailboxes with a baseball bat from a moving car) is somewhat popular with teenagers but it is seriously bad news that can carry a hefty federal charge that includes large fines and/or prison time. I had friends that got caught doing it when I was in high school. They eventually got off but not before it almost bankrupted and broke up their families. Mail fraud is another thing you want to stay far away from. If you want to scam somebody, do it in person because using the mail to do it is a separate but very serious crime.
Apologies,I meant we put them through the letterbox.