Finding maps locally is hit or miss, with little rhyme or reason as to how useful or effective they will be. I recommend bringing with you whatever maps you think are essential. I always bring the best maps I can find, and I’ve never regretted it.

If you need a detailed and updated map of a specific place, you can use Google:

International Map Trade Association (IMTA)
IMTA members are the companies that create and sell the maps, atlases, globes and map-related products you use.

Map Link
Tell them where you are going and what you’ll be doing and they’ll give you expert advice on which maps will be best.