Is it in a city? No
DO people Visit it? Yes
Is it a forest? No

is it mentioned in LOTR

is it mentioned in LOTR Yes

is it the gap of rohan?

is it the gap of rohan? No

I doubt anyone is going to get it by random guessing. It might be a good idea to ask narrowing down questions...

Is it west of the Misty Mountains?

Is it west of the Misty Mountains? No

Do people live in/by it?

East of the Misty Mountains?

Is it south of Mordor?

Is it wet?

Do people live in/by it? Temporarily
East of the Misty Mountains? Yes, but it is also south of them.
Is it south of Mordor? No
Is it wet? Yes

The dead marshes?

The dead marshes? No

Nindalf, aka the Wetwang?

Nindalf, aka the Wetwang? No

Isengard?

Henneth Annun?

Isengard? No
Henneth Annun? No

Has a member of the fellowship visited this place?

Has a member of the fellowship visited this place? Yes

Did all of the fellowship visit this placE?

Did all of the fellowship visit this placE? No

Has this place been visited by a hobbit?

Has this place been visited by a hobbit? Yes

Osgiliath?

Osgiliath? No

Visited by a dwarf?

Was it visited by Frodo?

Tol Brandir?
 

Or is it a hill/mountain?

Is it a river?

Visited by a dwarf? No
Was it visited by Frodo? Yes
Tol Brandir? No
Or is it a hill/mountain? No
Is it a river? No

Visited by Merry and Pippin?

Visited by Merry and Pippin? No

is it ithilien?

is it ithilien? No

Is it Minas Morgul?

Is it Minas Morgul? It's not a city, so I would have to say No

the cross-roads?
 

did Frodo stay there over a day?

The cross-roads? No
did Frodo stay there over a day? No (Meaning 24 hrs, as opposed to day from dawn to dusk)