My mom & I live at home together, but every night my mother wants to "go home" around 730pm. What to do?

"going home" may mean to a time when they were well and able to care for themselves.
"going home" can mean she wants to be safe.
Reassure her that she is safe.
Reassure her that this is her home also.
If she still insists that she wants to "go home" tell her that it is getting late and she better stay the night. Help her get ready for bed, pointing out that her things are all right there, night gown (or pj's) toothbrush, hair brush...so she must have planned on spending the night anyway. As well as a change of clothes for the next day.
Tell her that you will have a little breakfast in the morning and not to worry.

AKdaughter77, I heartily second your suggestion of talking to your parent about "home" and what s/he means by that and what she remembers, and ideally lead her through time to the present if possible. But why feel awful about lying? - there's no lying involved, it's just that the truth is complicated.

Her "home" could be her childhood home not the last one she lived in.

I agree with the others. I took a seminar on people with dementia. Trying to get them to accept the reality won’t work. You’re best bet is to distract her or get her to talk about where “home” is to her and what she’d like to do there. See if it’s an activity you can reproduce somehow. It’s awful having to lie to someone you care about but just remember, she won’t know you are lying. I took the class because my dad started in his early 80s telling me his dreams that featured him trying to get back home (he doesn’t have dementia yet!) so that when he did decide to “wander” or complain about not being “home” I would be better prepared to know where he meant. Turns out it was his first house he had when he was a young man in California. They also advised keeping all cash and credit cards out of reach so that the person can’t catch a bus to wherever they’re trying to get to. It was sponsored by The Cleveland Clinic. Worth looking into.

Keefer, time to start using what we call "therapeutic fibs". Tell Mom "your house needed repairs and they haven't finished". Don't say anything more. Chances are your Mom will accept that, and forget about it until she asks once again. Use the same fib. You can try others such as "the street is being re-paved", or what you feel will work best.

I had to do that for my Mom who at 98, living in a nursing home, and wanted to go visit her parents. I found she accepted when I said "your parents are visiting the old county", she would smile and say "that is nice".

Wanting to go home is a very common request for someone with dementia. It can mean many things. She may be uncomfortable in her surroundings, or may not recognize or be able to relate to where she is. It could be a sign of anxiety, you just don't know. She may be thinking of her old home as a youngster. There is no place she would recognize as home.

There are some things you could try. What won't work is telling her that she is home. Ask her to tell you more about home. Something like, “You must miss home, tell me about it”. Ask what does she like about home. If it's always at 7:30, which may indicate some sundowning also, you might say, “It's a little too late right now, we'll go tomorrow”, then redirect her attention to have a snack, watch TV, go for a walk. You might even try taking a short drive and returning.

Learn more about dementia and what other behaviors you can expect.