Irwin's Farm is a small farm outside the Hub owned by Irwin. Recently taken over by raiders, the impoverished farmer squats in a ruin in the downtown area of the Hub, waiting for help. The player can help Irwin, which is also the only method to access the location (outside using number keys on the town map to activate it). The player has to be at least level 5 for Irwin to accept help.
The farm house has seven raiders in total, four armed with firearms (one with a shotgun and one with a Desert Eagle .44 in the main room, with another armed with a Desert Eagle in the room next to the entrance, and one with a 14mm pistol in the back) and three with close combat weapons (one spiked knuckles and combat knife). The confined space means that the player has to have good armor (at least leather armor) and high damage weapons or support from party members. Rushing into the house will mean getting surrounded and killed.
Solutions include dosing them up with drugs (Psycho works best) or blocking the entrance with the player character, so that party members can't enter the farmstead, but can still offer assistance. Giving followers stimpaks is a very good idea as well. In general, this is a fairly difficult encounter for lower level characters, but can be breezed through with the right equipment - say, if the player has scrounged up enough funds to buy the combat armor or sniper rifle (or both) from Jake in the Old Town.
Behind the scenes
Irwin's Farm appears only in Fallout.