Whitman finds an exuberant connection with all of America in this poem. He feels the energy of all the people in the country from the blacksmith to the butcher boy to the negro—and even the team of horses the "giant" negro drives. He writes:

I behold the picturesque giant [the negro] and love him, and I do not stop there,

I go with the team also.

In me the caresser of life wherever moving, backward as well as forward sluing,

To niches aside and junior bending, not a person or object missing,

Absorbing all to myself and for this song.

He sees himself as part of everyone and everything. This universal self derives its life and energy from its awareness of all others and the universe.

Shortly after the passage quoted above he offers a long list of all the Americans he feels kinship with, young and old, male and female, from the whaler to the Native American to the judge. He writes:

Whitman’s concept of “America” springs from a paradox that lies at the heart of his poetry, namely, the difference between the individual and the collective. That is, the idea of freedom is very much an individual thing, whereas the idea of a nation is a collection of individual experiences and shared experiences. Whitman argues that he himself (the poet) is the means for combining these two opposites. It is the poet (or the poem) that is able to register individual experiences and at the same time contain or “catalog” them all. So, in a real sense, “America” is Whitman; the “America” he means is not merely a political state, but a kind of summation of all the spiritual and emotional striving of the people. This is, on purpose, a vague and approximate formulation on his part; ”Song of Myself” (which could also be called, just as accurately, “Song of Yourself” or “Song of America” or even “Song of the Cosmos”) does not make a conventional argument about what America “is.” I suppose in the largest sense to “be an American” for Whitman means to be alive, to be “untranslatable,” to sound the “barbaric yawp over the roofs of the world.” 

Walt Whitman has a lot of things to say about America and what it means to be American. In his poem "Song of Myself," one of the ways in which he defines what it means to be American is his exploration of the Democratic Self.

Whitman's Democratic Self is an idea that equates the individual with the universal. Consider, for instance, the following lines:

And these tend inward to me, and I tend outward to them,

And such as it is to be of these more or less I am,

And of these one and all I weave the song of myself. (327-9)

This quote comes at the end of a long list describing many people and scenes from diverse walks of life. Basically, what Whitman is saying here is that the self encompasses a diverse array of experiences and other selves. This idea is particularly important for Americans, who (theoretically) exist in a diverse society that relies upon a multitude of different opinions and beliefs to function. Indeed, this universal self draws upon the ideals of Democracy that America relies upon, and so the Democratic Self (the individual who exists within and draws upon multiple perspectives and personas) becomes a quintessentially American experience. 

Whitman references this idea in later sections by referring to himself as "a kosmos" (497) and by claiming, "I am large, I contain multitudes" (1326). Thus, much of "Song of Myself" focuses on developing this American idea of the Democratic Self, the self that relies upon diversity of opinion, lifestyle, and experience for existence. Whitman's conception of the individual mirrors the ideals of American Democracy, which seeks to incorporate the lifestyles and cultures of many different people to exist. Of course, much could be done to criticize Whitman's idealistic view of both American society and of the individual, but the fact remains that the poet's democratic conception of what it means to be an American remains radical and intriguing to this day.