Dee ihe na-aga n'ihu maka paragraf a - N'ọgbọ agha nke ọwụwa anyanwụ, ndị agha Union nke Potomac, nke Major General Joseph Hooker nyere iwu, wakporo ndị agha Confederate nke Northern Virginia nke General Robert E. Lee nyere iwu na Agha nke Chancellorsville. Hooker zubere ịkwaga ọtụtụ ndị agha ya gburugburu na azụ ndị Confederates tupu Lee nwere ike imeghachi omume ma mee ka Lee laghachi azụ mana ndị agha Union jiri nwayọ nwayọ wee kwụsị obere ndị agha Confederate, nke ndị agha ndị ọzọ nọ na Confederate wusiri ike. Lee zigara otu kọlụm nke Thomas J. Jackson na-eduzi gburugburu aka ekpe Hooker, nke wakporo awa ole na ole tupu anyanwụ adaa na Mee 2; mwakpo a na mwakpo ndị ọzọ nke Confederate na-esote ụbọchị mere ka Hooker laghachi azụ na Mee 6. N'oge agha ahụ, ọkụ ndị enyi Jackson gbara merụrụ ya ahụ ma nwụọ mgbe ụbọchị ole na ole gasịrị. Lee hazigharịrị ndị agha ya na-esochi mkpọsa ahụ wee malite mwakpo nke mpaghara Union na June, na-agafe na ndagwurugwu Shenandoah na Pennsylvania; A napụrụ Hooker iwu na June 29, n'ihi esemokwu na-aga n'ihu na gọọmentị banyere ndị agha nke Harpers Ferry, ma dochie ya na Major General George Meade. N'oge Agha Gettysburg site na July 1 ruo July 3, Meade jisiri ike gbochie mwakpo Lee ma na-ebute nnukwu ọnwụ na nloghachi. A manyere Lee ịlaghachi na Virginia; Meade sochiri ya n'azụ ma enweghị ike ịchọta ohere iji kpochapụ ndị agha Confederate kpamkpam. N'ọnwa Ọktoba, Lee gbalịrị ịhapụ ma bibie Meade n'oge Bristoe Campaign mana ọ dara na mwakpo nke ọnọdụ ndị Union na Battle of Bristoe Station na Ọktọba 14. N'ịbụ onye ndị ọchịchị Union manyere, Meade gbalịrị ịwakpo ọnọdụ Lee n'akụkụ Mine Run
; agbanyeghị, Lee nwere ike ịtọlite usoro nchekwa siri ike gafee usoro ndị Union na-aga n'ihu. Meade weere ọnọdụ ndị Confederate dị ka nke siri ike ịwakpo ma laghachi azụ.