The Battle of Yan Ford was a battle that took place along the southern banks of the Yellow River in the late Eastern Han dynasty. The battle was closely preceded by the Battle of Boma, and was part of a series of engagements leading to the decisive confrontation between the rival warlords Yuan Shao and Cao Cao at the Battle of Guandu in 200. Following the death of one of Yuan Shao's elite generals, Yan Liang, in the previous battle, the death of another famed general Wen Chou in this battle greatly demoralised Yuan's army, which was heading towards Guandu.

Cao Cao and Yuan Shao were heading toward a direct confrontation since the late 190s, and the first months of 200 saw the opening of hostilities at the Battle of Boma after years of manoeuvring. With a feint, Cao Cao was able to split off Yuan Shao's main force gathered at Liyang (黎陽; northwest of present-day Xun County, Henan) across the river from Boma (白馬; near present-day Hua County, Henan) and hence relieve the siege at Boma, killing Yuan Shao's attacking general Yan Liang. Considering that the position at Boma was unsuitable for a determined defence, Cao Cao voluntarily abandoned the outpost and evacuated its population and supplies to the west along the river. With that, Yuan Shao finally crossed the Yellow River in pursuit of Cao Cao's baggage train. However, Cao Cao was not satisfied with just abandoning all lands between Guandu and the river to the enemy — he had also wanted to make his enemy pay dearly by resisting the enemy advance during the predetermined fallback to Guandu.

As a result of Cao Cao's feint during the Battle of Boma, Yuan Shao had brought the advance-guard of his army up the Yellow River toward the western Yan Ford (延津; north of present-day Yanjin, Henan). It was probably at this ford that Yuan Shao's army made the crossing, which was unhindered by Cao Cao. By this time, Yuan Shao was almost due north of Cao Cao's defensive positions at Guandu and his base in the capital of Xu City.

Cao Cao's men also reached Yan Ford and made camp below a ridge known as the Southern Slope (南阪), 20 li west and 50 li south of Boma. As Cao Cao's position was on the southern side of a dyke some distance away from the river (meant to control seasonal floodwaters), his men were concealed from Yuan Shao's view while Cao Cao had to send lookouts to scout for enemy movements. The lookout first reported five to six hundred enemy cavalry on their way, then reported that there were slightly more cavalry than before and the size of the infantry force was beyond measurement. At this point Cao Cao stopped the lookout from reporting, and had his horsemen undo the saddles and release the horses.

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