Though it varied from state to state, the best answer is the United States was filled with sadness yet possibility, seemed emptier than before, war continued, peoples continued to be displaced, and in the South, destitution and deprivation reigned. I'll start with the North and then go to the South, before turning to the West.

The elation that came with the surrender of Robert E. Lee's Army of Northern Virginia and Joseph Johnston's Army of the Tennessee was soon dashed with the assassination of Abraham Lincoln. Somber silence is perhaps an understatement. Hence the rush to capture Lincoln's killer and the by-and-large show trial of the conspirators, including the railroading of Mary Surratt, whose only crime was allowing the assassins to use her home, as her son was one of the conspirators.

Despite this sadness, the North had much to look forward to. With the South prostrate, northern capitalists no longer had to contend with southern politicians who would hamper or redirect their efforts to build a transcontinental railroad. Tariffs and other customs could be set at will and business seemed ready to unleash its full power as resources and land now all could be dominated by northern interests.

However, the country did seem emptier, particularly in the smaller farming towns that dotted the North. Every single town experienced loss. The Civil War Trust puts northern total casualties at 596,670. Sons and fathers were either killed or came back shells of who they were. The opportunities out West for men with military experience meant many would travel into the frontier and not return to their former lives. This emptiness, in the North at least, was temporary, as surging immigration brought new life to urban centers. However, smaller towns would suffer, helping cause the rural flight to the urban centers.

However, all was not quiet. One thing people forget is that during the war, Lakota Indians rose up and the army under disgraced general John Pope was sent to quell the disturbance. With the end of the war, the Union could take its full might and end any competition for sovereign control over the whole of U.S. claimed territory. One by one, Native tribes were subdued, at great loss of life. With Black "equality" ensured, at least before the law anyway, the U.S. had to decide how to fit this new motley crew of races into the U.S. pantheon of race relations. Chinese were excluded. Natives forcibly incorporated, Hispanics were dealt with as their color and condition required. Where Hispanics were looked more light skinned and where they held economic power, they were incorporated, where darker, they were shunned and exploited. War would not cease in the West for the better part of the 19th century, fed by men who had cut their teeth in the Civil War. "Cowboys" desperados, and other outlaws found ample employment, as did Pinkertons and other companies of deputized gunmen.

Now to the South. Clearly, sadness reigned. With no victory, there was no silver lining. Without a doubt, the picture you would see of the South is that of destitution, destruction, and abject suffering. However, for some African Americans, a glimmer of home seemed possible, until it was ruthlessly snuffed out. Southern males experienced 490,309 total casualties during the war. However, I believe this does not represent figures from inter-guerrilla activity, reprisals, and other horrific experiences that were experienced on the Confederate home front. Every town in the South undoubtedly had families who lost sons, fathers, and brothers. A eerie emptiness was surely felt. The men who returned, were broken, battered, and psychologically tormented. So much so that one Confederate woman lamented their new role as having to care for these shells of their former husbands. Now the entirety of the South was not subject to devastation, just those parts that experienced prolonged exposure to armies, both North and South. Texas, parts of Arkansas, Kentucky, Mississippi, Alabama, and other southern states did not have complete destruction. But areas like Central Georgia, the entirety of Tennessee, Northern Virginia, East Florida, coastal South Carolina, and etc. all witnessed widespread destruction. Farms and cities burned, agricultural production stripped, and industrial goods gone. At the time of surrender, historians such as George Rable in his work But There Was No Peace: The Role of Violence in Reconstruction, contend that had the Union moved with haste, the southern people may well have accepted any agreement forced upon them. But this was not done, to the lament of African Americans.

African Americans have a particularly jaded experience with the end of the war. On the one hand, where the Union army had moved through and established freedmen areas, like the South Carolina Sea Islands, their life, culture, and prospects flourished. On the other hand, in the untouched parts of Texas and elsewhere, freedom did not come till late 1865, and by then, political events had castrated many possible opportunities for black freedom.

War also continued in the South. Guerrilla violence continued throughout the period. Lynchings, murders, and intimidation were the law of the land. With no major occupying force in the area, former Confederates could assassinate at will. Only when the Union Army intervened, at the prodding of the Grant administration and with passage of the Ku Klux Klan Act, could extra legal violence begin to be dealt with. Even then, we find substantial violence throughout the Reconstructed South, which did not end with the end of Reconstruction.

North, South, and West. Peoples were continually displaced, either by circumstance, force, or the cruelty of chance. It is very hard to place where many people went. For instance, from St. Augustine Fl, half the prewar population were gone at the end of the war and very few returned by 1870. Where did they go? What did they do? We may never know.

So, to reiterate, sadness, emptiness, desolation, endemic warfare, and displacement. The Civil War was a tragedy, yet also an opportunity to make a more perfect Union. Whether that more perfect Union could actually be enacted in the era, is a debate for another day.

Sources: George C. Rable, But There Was No Peace: The Role of Violence in Reconstruction; Drew Gilipin Faust, This Republic of Suffering: Death and the American Civil War; Eric Foner, Reconstruction: America's Unfinished Revolution.