Burgoyne decided on a three pronged attack. The largest force, of 2000 men commanded by General Fraser, was to try and outflank the American left. The British centre, 1100 men under General Hamilton, and the British left, a similar sized force under Baron von Riedesel, were to pin the American forces in place on Bemis Heights until Fraser could hit them from the flank. At 10 in the morning on 19th September a cannon was fired to signal the start of the British advance.
As the British began their advance, the Americans were in place behind their fortifications. The bulk of the American army was formed from regular Continental Troops. Gates was in personal command nearest the river, with General Ebenezer Learned commanding the centre, and Benedict Arnold on the left commanding a mixed force of Continentals and militia.
If the British plan had been allowed to develop it may have had some success. However, Arnold recognised how vulnerable the British were while advancing, and pestered Gates to allow him to advance. Eventually, at about noon, Gates gave in and allowed most of Arnold's wing to advance. It was this advanced force that met with the British centre at Freeman's Farm, one mile north of the American positions on Bemis Heights. It was here that the battle developed. The American assault was determined and at one point the British line was forced back, although a determined British counter attack managed to regain the line. Benedict Arnold was at the forefront of the fighting, and his attacking spirit helped inspire his men. The British had not been expecting the Americans to put up such a good fight, and as the afternoon drew on, it was the British who began to weaken.
Both sides were fighting in isolation. Burgoyne had deliberately split his force, and was now suffering for it. Riedesel's command was struggling to climb up from the river to the battlefield, while Fraser never managed to reach the battlefield. On the American side, Gates refused to reinforce a furious Arnold, who believed that he could have destroyed the British army with a little help from his commander. Gate's attitude can be defended - for all the ferocity of the fighting, Arnold was only facing at most a quarter of the British army, and Gates could not risk weakening his main position with Fraser's strong force somewhere in the woods.
Finally, as evening drew in, the British position was saved by the arrival of Riedesel. Arnold was forced to withdraw, and the British held the battlefield. However, they had suffered very heavy casualties, losing 556 regulars killed and wounded, half of Hamilton's force. The Americans had also suffered heavily, but they were able to replace their losses, and indeed over the next few weeks the American army was to grow dramatically. Burgoyne was of the opinion that a British attack on the next day would have defeated the Americans, but his own army was in far too poor a condition to consider such an attack. Burgoyne then delayed a second attack further on news that Clinton was launching an attack up the Hudson from New York. By the time Burgoyne was ready to attack again, the moment had been lost.