The Jönköpings regiment, as were most of the units in Karl's main army, were indelta infantry. As the name suggests, they were raised in the town and county of Jönköping, located in south central Sweden at the bottom of Lake Vättern. As today, Jönköping County is a populous area so they could raise a regiment as a county where normally an entire province did so. The province in question was so populous, in fact, that a second county in it, Kronoberg County, also raised a regiment. There was talk in the 17th century of amalgamating both regiments into a Smaland infantry regiment, but this never came to pass.
The Jönköpings regiment started the Great Northern War in Sweden's North German posession of Pomerania and participating in the Holstein campaign in 1700. In 1702, it went to Poland to join the King's Army (which had arrived there from its victorious campaign in Russia) and remained with it until its surrender at Poltava. After Poltava, the Jönköpings regiment was reraised, fought in Skane and was then sent to Germany again, where it ended it second life at Stralsund when that city surrendered to the Allies in 1715. The regiment was then raised a final time to participate in the abortive 1718 Norwegian campaign.
In the battle of Poltava, the Jönköpings regiment - which was down to a single battalion in strength by then - started out as the rear unit in the column of General Sparre on the extreme left of the advance through the redoubts. In the confusion of night and unclear orders, the Jönköpings and the regiment in front of it (Närke-Värmlands) somehow veered of to the right and got implicated in General Roos' attacks on various redoubts. They stayed with Roos throughout the rest of the battle, being chased away from the main infantry advance and eventually ending up surrendering in sight of Poltava itself. They did not see action in the main fight later that day.
The uniforms of the Jönköpings regiment are the basic blue Swedish coat with red facings, leather vests and breeches and red stockings. In 1700 the unit had red lined Karpus, but these were replaced by white braided hats in 1702, so I have opted for the latter to represent the unit as at Poltava. There is no information on the grenadiers' headwear, so I have given them the iconical mitres.