The battle of Naseby was one of the most important battles in British history. It took place on 14 June 1645 in the last but one year of the First Civil War between King Charles I and Parliament. When I studied the origins, course and aftermath of the Civil War as a History undergraduate (my special subject in my last year was "Oliver Cromwell and the English Revolution"), I had little interest in the military side, but since then I've found battlefields both mournful and fascinating places. Unlike, say, Culloden (a stand of pines is right in the middle of the battlefield, so you can't stand on one side and imagine how it looked to see enemy forces drawn up on the other side: besides, not far behind the Jacobite position now are brick houses of the Inverness suburbs), or unlike the other most decisive Civil War battlefield at Marston Moor (road through the middle, rubbish dump by the monument when I visited), Naseby is relatively well preserved, though a motorway spur was driven through an outlying area.
The site is in Northamptonshire but very close to Leicestershire to the north, in rolling, mainly open country of fields, small woods and villages. The monument and small interpretative display are just in front of the centre of the Parliamentary position: from there you can easily see the ridge where the Royalist army started and Sulby hedges, which played a key part in the battle, to the Parliamentary left. In 1645 the roads in the area were rough tracks and some ground now farmed was marshy.
The war had been going on for three years with little sign of an end. Parliament's advantage from the major victory at Marston Moor outside York the year before had been squandered in a disastrous Westcountry campaign in which many of the veteran Parliamentary infantry had been killed, many after surrender and disarming by Cornish locals. Parliament had organised a "New Model Army" to clear out half-hearted officers, but the infantry were very green (some got their first weapons training on the march a day or two before the battle)and many were unenthusiastic, unlike the highly-motivated, well-trained cavalry. The Royalist army had plenty of experienced infantry; their cavalry ("cavaliers")were confident but ill-disciplined.
The King's main army had captured Leicester, a city of strong Parliamentary and Puritan sympathies, and had slaughtered a number of civilians. The Parliamentary General Sir Thomas Fairfax had been besieging Oxford, but was ordered away to engage the King, which he did. The King was hoping for cavalry reinfoircements but they never arrived; in contrast, East Anglian cavalry under Oliver Cromwell reinforced Fairfax the night before the battle. As a result, while the numbers of infantry on the two sides were similar (with probably a slight Royalist advantage), Fairfax had a big advantage in cavalry and also some dragoons (light cavalry who operated like modern motorised infantry, travelling fast but fighting on foot). On the Royalist side the King was in ultimate command but under him, control was with Prince Rupert.
The Parliamentary left and Royalist right rested on Sulby hedges. Fairfax sent dragoons behind the hedges so they could deliver flanking fire. Some accounts say the Royalists tried to occupy this point too and were driven off. The King's army charged and won early success against the green New Model infantry and some of the cavalry, but Prince Rupert's cavalry pursued fleeing Parliamentarians away from the main battlefield while Cromwell, having defeated the outnumbered Royalist cavalry facing him on the Parliamentary right, turned to join the infantry battle, as so did the dragoons (on horseback, which was not at all in the rulebook). The Royalist cavalry scattered and the infantry then had no chance, though many fought on. The King's cause never recovered.
I've visited the site perhaps four times and it has a strange power for me. It is not hard to imagine myself there on 14 June 1645.
Other things to attract visitors? A short way to the north over the Leicestershire border is picturesque Market Harborough. There's a good network of footpaths and it's pleasant if unspectacular walking country. There's plenty of good pubs, many of them in the characteristic, mellow local yellow sandstone.