How do I get to the De'Arnise hold? I can see it on my map but it is greyed out. HELP!!!!

i had the same problem. just leave the city from the City Gates Map and you should be able to get to the hold.

When an area is "grayed out", you need to go to the city gates area first. upon leaving the city gates area it will be active for you.

It's similar to Baldur's Gate City in BG1, you had to visit something adjacent to the part of the city in order to get to the new location.

But once you've visited the Gate District in BG2 you should be able to travel out of any part of the city from now on to any map location. -at least that's the way it's been for me.