I went to Japan in 2011.
My husband has been working on Mars since 2011.
My father finally admitted to drug use in 2011.
It's the 2011 year. I think the meaning is pretty obvious. This just means year 2011 or simply 2011.
The reading is a little trickier. You start with two thousand (二千／にせん), then you need to add eleven to it (十一／じゅういち). Then, you simply add the reading for 年 which you already know. You can assume it's the on'yomi reading because it's attached to something else, like a jukugo. From there, you get the entire reading.