I am trying to power a 240v well pump 1100' from a breaker box. What type of wire and breaker should I use. Currently I have 10-2 run about 350' to a junction where I atttach a generator. I am trying to conver a span of 750' from my breaker to the existing junction.

Need to know the amperage draw of the motor, or you can use this calculator:

Southwire - Delivers Power

For example, a 10 amp load at 240 volts and 1100 feet will need a minimum of #2 aluminum.