Why does Huck go ashore? What does he find out?This is when he dresses up as a girl while on the island with Jim.

Huck goes to shore partly just because he is bored and partly to see if there is any news about the town's reaction to his and Jim's disappearances.  He learns that word of his supposed murder has gotten around, and that although at first it was believed that Pap killed Huck, when people found that Jim had run away as well, they concluded that Jim must have killed Huck.  There is a $300 reward for the capture of Jim.