Uhhh... Not necessarily... You probably own the valve... But them doing it gives you a better chance of it being closed without breakage, if for no other reason than they do it all the time. (Open/close curb stops that is...)

Don't give up without trying it. Just don't force it if you have to use too much muscle. If you're concerned about breaking it, you won't. It may turn easily.

Thanks guys, Yes, I do own everything from the street up to the house. I'm getting a wrench today, and I'm going to gently try turning it off. If it resists I'll call the water company and let them come out and do the forcing. Now I need to get a American made shutoff valve for the main shutoff inside. I don't trust the Chinese stuff. I understand a lot of them have bad castings. Stay cool. It's hot here in St. Louis, and way too dry.

If it resists I'll call the water company and let them come out and do the forcing.

...i'd call them anyway. let them get down in the hole and turn it off. they'll wait for a call back when you're through changing the inside house valve to turn it back on for you.

i've done it many times, less work for me. besides it built in to your water bill

I had to do something like you are considering once and the street valve didn't shut off completely. Had to call the water company to have them replace their valve before I could do any soldering inside. This was in SoCA where the residential valves were usually easy to turn.

"...replace their valve..."

Again, mostly for the OP's benefit, in many communities, the curb stop (valve) itself is the property of the homeowner, NOT the water company. Same for the sewer connection - the wye is the owner's property / "responsibility".

Confirm ownership/responsibility with the local municipality.

Yes, it is necessary to confirm the street valve ownership. In SoCA the valve is usually part of the meter and there is no question. In fact, there the valve is on the street side of the meter. Some cities there don't allow homeowners to mess with the valve, but I never had a problem with that.

And they should make sure the shut offs work. Many times they have not been used in decades and they are frozen shut. Sometimes they break in the closed position and sometimes they break in the open position. Around here there is a shut off before and after the meter. Its good to have 2 in-case one doesn't work, but I had a problem in an older house where both valves were broke, the gate valve stem snapped off and the handle kept turning and nothing happened.
The water utility around here is the city, and they come out to shut the outside in-ground valve off if needed, but I don't think they prohibit a homeowner from doing so.

That's good advice.

Probably the safest way to handle it is to call the water co. and tell them you need to shut the water off, then be there when the guy comes to do it.

Then ask the guy if it moves freely and can you do it.

If I didn't have a shutoff at the house, I'd want to make sure I could turn it off in an emergency whether I was allowed to or not.

Well, I decided to let a plumber put a new ball-type shutoff valve to replace my 36 year old shutoff valve in my basement. I found out that our water company here in St. Louis County will not come out and turn the water off, and we do own the valve and meter out in the front yard. I figured I'd let the plumber turn off the valve outside in case it was frozen in place, and do the new ball valve in the basement. I'm capable of cutting copper pipe and sweating fittings, but with a ball valve, I understand us amateurs can overheat it and mess up the internals. The interesting part is that the plumber didn't solder the valve in either. He cut out a section of the 3/4" pipe, and replaced it with the valve, which had sections of pipe already sweat and screwed into each end. He then used couplings that he didn't have to solder. The couplings have o-rings and he had a power crimping tool which crimped them onto the existing pipe. He said they use them all the time, with no leak problems. Of course, they aren't something us amateurs could do ourselves. I hope these couplings are proven to be good, and that I won't have leaks down the line. Again, no matter how old you are, you learn new techniques all the time. This site is great, and it's important that we post our solutions so others can learn, as well. Thanks, Bill