At the heart of The Adventures of Huckleberry Finn is Mark Twain's love of the mighty Mississippi River upon whose waters he himself spent many a day. On their raft on this river, Jim and Huck spend halcyon days as they are free of the corruption and hypocrisy of society, for they are friends and equals upon the raft.
This peacefulness of the river is indicated by Huck's descriptions, such as how they watch the daylight come,
Not a sound, anywheres--perfectly still--just like the whole world was asleep only sometimes the bull-frogs a-cluttering, maybe. The first thing to see, looking away over the water, was a kind of dull line--that was the woods on t'other side...then a pale place in the sky; then more paleness, spreading around; the the river softened up, away off, and warn't black any more, but gray; you could see little dark spots drifting along, ever so far away....
A sense of freedom is also indicated in such passages as this one:
Sometimes we'd have that whole river all to ourselves for the longes time. Yonder was the banks and the islands, across the water; and maybe a spark--which was a candle in a cabin window--and sometimes on the water you could see a spark or two--on a raft or a scow, you know....It's lovely to live on a raft. We had the sky, up there, all speckled with stars, and used to lay on our back and look up at them, and discuss about whether they was made,...We used to watch the stars that fell, too, and see them streak down. Jim allowed they'd got spoiled and was hove out of the nest.
After midnight when the people on shore retire for the evening into their homes, Jim and Huck watch while the shore remains black for two or three hours, informing them that they can safely move around. But, when they see a spark in the morning, they become aware that they must "hunt a place to hide and tie up, right away." Conclusively, the society represented by the lights in the dwellings, is to be feared by Jim and Huck while the raft represents freedom and equality.