On 1st October 1645, the Royalist garrison at Sandal surrendered the castle at 10 am. The garrison consisted of ten officers and ninety men. They surrendered 100 muskets, 50 pikes, 20 halberds, 150 swords and 2 barrels of gunpowder. No artillery was mentioned in the inventory. The Royalist defenders marched to Welbeck House in north Nottinghamshire.
In early September 1645, Colonel General Poyntz tightened the siege lines around Sandal Castle and obtained four great siege guns from Hull. With protection afforded them behind earthwork batteries, the Parliamentary forces began bombarding the Castle with 60 pound cannonballs: the normal sized cannonball was 28 or 32 pounds. At the time of this bombardment, the castle was garrisoned by 100 men. After several days of bombardment, some breaches had been made in the walls of the castle.
On 30th September 1645, Parliament’s Colonel Robert Overton made preparations to storm Sandal Castle but after a parley the defenders agreed to leave on favourable terms.
During the siege of Sandal Castle, on 17th June 1645, the well tower bore the brunt of the bombardment. More than forty cannon balls were found on the motte slope outside the tower.
At the end of June 1645, Sandal Castle was besieged by a force of 300 dragoons under Colonel Morgan. These were mounted infantry with matchlock muskets. However, with insufficient fodder for their horses, they could not continue the siege and withdrew to Pontefract.
In the first week of May 1645, Royalist Captain John Benson and three of his men secretly left Pontefract Castle to strengthen the Sandal garrison, which had suffered eight men killed and several others wounded and captured when a foraging party had been ambushed by Parliamentarian forces.
On 20th May 1643, Parliamentarians, under Sir Thomas Fairfax, marched towards Wakefield with 1,500 horses and infantry. Fairfax launched an attack on Westgate and Northgate. The fighting was fierce but they suffered few casualties. Fairfax took Wakefield and took prisoner all the Royalist officers. His forces were too weak, however, to retain the town and so he marched away in triumph with 1,500 prisoners, three captured cannons, along with arms and other valuables.