If your city (and some of the surrounding area,surviving suburbs, farms etc) was cut off from the rest of the world, could it survive alone?

No way. Things would decline within a week. All out war would occur within a month.

I live in the country surrounded by goats, cows, chickens, horses, alpacas, and all types of wild life. Many of us grow our own veggies/fruits and some of our neighbors have generators... We had to survive for 3 days with no power, water, light... 2 winters ago. But we had a tiny wood-burning stove that we used for heat and to melt snow into water. Oh - we did cheat though by ordering Dominoes Pizza and we ate it by candlelight. lol It's possible our community could survive on it's own, but it would be like going back to the 1800's. Don't fancy that too much!

If my city (Minneapolis) can manage to hang onto the major surviving suburbs and surrounding farms, and if we were to keep the potential chaos outside make-shift city walls and roadblocks...we would probably become a pretty powerful city-state if the sh*t ever really hit the fan.

Me And MY PEOPLES' SHALL do WhatEver It Takes for SURVIVAL & For US To Keep IT AFLOAT Before SunRise ON AN EVENING BASIS!!