Every day KPA resistance had increased on the road to Yongdungp'o a big industrial suburb on the south bank of the Han, 3 miles (4.8 km) southwest of Seoul.

[3]: 516–7 On the morning of 21 September, the 5th Marines, after repulsing an enemy company-sized counterattack, advanced southeast astride the rail and road lines paralleling the Han River.

Their attack groups left Yongdungp'o, crossed the rice paddies and Kal-ch'on Creek, a sizable stream flowing north past the west edge of the city into the Han, and arrived on Hills 80 and 85 to find them undefended.

[3]: 517–8 Simultaneously with the North Korean predawn attack against Hills 80, 85, and 118, a battalion-size force led by five T-34 tanks left Yongdungp'o on the Inch'on highway to counterattack the 1st Marines.

[3]: 519–20 That afternoon the North Koreans apparently were too busy in the battle at the western edge of the city to give much attention to the unit in their rear, although small groups did make feeble efforts against it.

[3]: 520 The North Koreans, after their failure during the night of 21-22 September to drive Barrow's company from its advanced position at the eastern edge of Yongdungp'o, apparently abandoned the city before daybreak.

[3]: 520–1 As the 1st Marines fought its way along the Inchon-Seoul highway and into Yongdungp'o, the 7th Infantry Division protected its right flank and engaged KPA units moving toward the battle area from the south.

Naval aircraft bombed Suwon just before they arrived there at 18:00 and destroyed a large wooden structure on top of the ancient great stone wall at its East Gate.

[3]: 521–2 About 21:00 a full moon rose and Major general David G. Barr, having lost radio contact with the Reconnaissance Company, decided to send an armored force toward Suwon to find it.

During the day, Lt. Col. Charles M. Mount's 2nd Battalion, 32nd Infantry, seized the series of hills from 1–2 miles (1.6–3.2 km) south of the rail and highway bridges that crossed the Han into Seoul.

In this surprise action the battalion captured a regimental headquarters and much equipment, and broke the remaining enemy strength close to the south bank of the river opposite Seoul.

[3]: 523–4 While the 7th Division was securing X Corps' southern flank, the heaviest fighting in the battle for Seoul began at the city's western edge on 22 September and lasted four days.

From the crest of Hill 296 the KPA line curved in a gentle half-moon eastward and southward down spur ridges 2.5 miles (4.0 km) to the Han River, the concave side facing west toward the UN troops.

Their limited training, almost complete lack of experience in the use of supporting arms, and the absence of certain tools, e.g., flamethrowers, 3.5-inch rocket launchers, etc., rendered them, however, incapable at that time of successfully assaulting a heavily defended position.

In semi-darkness half an hour later a large enemy force, estimated to number approximately 1,000 men, violently counterattacked the 2nd Battalion perimeter on top of Namsan.

Almond at X Corps headquarters immediately sent a message to the Far East Air ForceS requesting a flare mission to illuminate the roads so that Marine night fighters could attack the enemy troops.

Buildings were heavily defended by machine guns and snipers, and on the boulevard the KPA had established a series of 8 feet (2.4 m)-high barricades of burlap bags, typically filled with sand, dirt, or rice.

The regiment's D Company turned down the Kaesong-Seoul highway toward the city, seeking to establish contact with the 5th Marines, but came under heavy enemy fire at 08:30 opposite Soedaemun Prison.

Richard J. H. Johnston, a correspondent for the New York Times who had lived in Seoul for four years, guided Captain Charles D. Frederick and his E Company men in the afternoon to the Soviet Embassy, where they pulled down the Red flag and raised the American at 15:30.

The 1st Battalion meanwhile captured the railroad station in the morning in fairly heavy action and then encountered a series of strongly defended barricades along the main thoroughfare leading northward into the center of the city.

[3]: 537 The breakthrough to the Capitol apparently caught some North Korean officials or stragglers there by surprise, compelling a hasty getaway, for upon entering the troops found hot food ready for eating.

A mile farther north, the KPA held the 7th Marines in check short of its objective, Hill 224 (37°37′23″N 127°00′25″E / 37.623°N 127.007°E / 37.623; 127.007) the key terrain feature on the other, west, side of the highway.

[3]: 537 On 23 September MacArthur sent a message to the Joint Chiefs of Staff in Washington saying in part, "I plan to return President Rhee, his cabinet, senior members of the legislature, the U.N. Commission and perhaps others of similar official category to domicile in Seoul as soon as conditions there are sufficiently stable to permit reasonable security."

MacArthur began forthwith to deliver his short address in sonorous voice and unhurried words: Mr. President By the grace of a merciful Providence our forces fighting under the standard of that greatest hope and inspiration of mankind, the United Nations, have liberated this ancient capital city... On behalf of the United Nations Command I am happy to restore to you, Mr. President, the seat of your government that from it you may better fulfill your constitutional responsibilities.The assemblage then joined MacArthur in reciting the Lord's Prayer.

President Harry S. Truman sent a message which said in part, "Few operations in military history can match either the delaying action where you traded space for time in which to build up your forces, or the brilliant maneuver which has now resulted in the liberation of Seoul."

From the Joint Chiefs of Staff MacArthur received a message which read in part, "Your transition from defensive to offensive operations was magnificently planned, timed, and executed.... We remain completely confident that the great task entrusted to you by the United Nations will be carried to a successful conclusion.

"[3]: 538–9 While the greater part of X Corps concentrated its strength before Seoul and was preoccupied with its capture, the blocking force of the 31st Infantry Regiment, 7th Division, 30 miles (48 km) below the city, was not without action.

Prisoners captured in Suwon by the Reconnaissance Company reported that a regiment of the 105th Armored Division was in Choch'iwon on the 18th, only 50 miles (80 km) to the south, and on its way north to help the Seoul garrison.

Ovenshine started the 2nd Battalion Task Force - composed of E, F and part of G Companies and two platoons of tanks on a wide, flanking movement southeastwardly toward Osan to attack the enemy positions from the rear.

[3]: 540 On the morning of the 28th, the American infantry withdrew at 08:30 almost 1 mile (1.6 km) westward from their overnight positions to make sure that they would not suffer casualties from air strikes scheduled to come in against Hills 113 and 92.