The 2013 County Championship season, known as the LV= County Championship for sponsorship reasons, was the 114th cricket County Championship season. It was contested through two divisions: Division One and Division Two. Each team played all the others in their division both home and away. Durham were County Champions for the third time in six seasons. The top two teams from Division Two, Lancashire and Northamptonshire, gained promotion to the first division for the 2014 season, while the bottom two sides from Division One—Derbyshire and Surrey—were relegated to Division Two for 2014.

  Team promoted from Division Two

  Team relegated from Division One

Defending champions Warwickshire had a disappointing start to the season, only managing a draw against newly promoted Derbyshire in a game that was dominated by bad weather. Somerset, runners-up the previous season, collapsed from 96/2 at the end of the third day against Durham to 186 all out, in the process losing by 48 runs to the champions of 2008 and 2009. Middlesex defeated Nottinghamshire by ten wickets at Trent Bridge. This was the latter county's first loss in an opening fixture for eleven years. Yorkshire, the other team promoted from Division Two in 2012, also lost at home—they fell to an innings defeat against Sussex, having been bowled out for just 96 in their first innings. Middlesex and Sussex jointly led the table on 23 points after the first round of games, with only Surrey yet to play their first match.

Despite having a slight first-innings lead, Derbyshire lost within three days against Middlesex at Lord's, having been bowled out for just 60 in their second innings, their lowest total against Middlesex. Surrey's first game of the season ended as a draw against Somerset, in part as a result of play being lost due to rain. Durham suffered a change in fortunes, falling to a heavy defeat against Warwickshire, who bowled them out for 94 after setting a target of 413 to win. Nottinghamshire picked up their first win of the season against Derbyshire, who had yet to win themselves on their return to Division One. Surrey drew their second consecutive game at The Oval, this time against Sussex, on a pitch that appeared to favour batting. Durham fell to a second consecutive defeat when Yorkshire set a record for the highest successful chase at Chester-le-Street. Warwickshire's tenth-wicket partnership denied Somerset their first victory of the season, holding out for 78 minutes in a match that was somewhat overshadowed by a series of questionable umpiring decisions. Middlesex, with two wins out of two, remained at the top of the table at the end of April, eight points clear of Warwickshire.

Durham subjected Nottinghamshire to a second consecutive home defeat, chasing a target of 183 in just over twenty overs. Derbyshire's miserable season continued with an innings loss against Yorkshire in a match that appeared to be heading for a draw. The matches between Middlesex and Surrey, and Sussex and Warwickshire were both drawn, allowing Durham to take the lead in the standings, with four other teams—Middlesex, Yorkshire, Warwickshire and Sussex—within ten points of the lead. In a match heavily affected by bad weather, Somerset hung on for a draw against Yorkshire, finishing on 61/6 after being made to follow-on. The weather also intervened in the match between Warwickshire and Middlesex at Edgbaston, which ended in a high-scoring draw. Durham's third win in five games, this time against Surrey, extended their Championship lead to 13.5 points over nearest rivals Middlesex.

Yorkshire's impressive start to the season continued when they inflicted an innings defeat on defending champions Warwickshire, dismissing them for under 200 in both innings. Somerset fell to their first home Championship defeat since the end of 2011, losing to Middlesex by nine wickets in three days. Sussex condemned the struggling Derbyshire to their fourth straight loss, with more than two sessions to spare at Derby. Surrey's difficult season continued when they lost to Nottinghamshire by over a hundred runs in a fairly low-scoring match. Sussex completed an innings victory against Somerset within two days, bowling their opponents out for just 76 and 108 in the two innings. Championship contenders Durham and Middlesex drew at Chester-le-Street after rain curtailed play on the third day. Durham ended up four wickets short of securing another victory. The game between Somerset and Yorkshire at Taunton also resulted in a rain-affected draw. Nevertheless, Yorkshire led the table at the end of May, a single point ahead of Sussex, and a further point clear of Middlesex. Somerset, Surrey and Derbyshire, all yet to win a game, were early contenders for relegation.

The match between fellow strugglers Derbyshire and Surrey ended in a high-scoring draw, while Nottinghamshire fell four wickets short of defeating early title contenders Sussex. The 2010 champions drew a second game in a week in a high-scoring encounter against Yorkshire. Draws also resulted in the contests between Middlesex and Sussex, Surrey and Warwickshire, and Somerset and Durham. Yorkshire defeated Middlesex by ten wickets, their first win at Lord's for 26 years. On the same day, Durham completed a narrow victory over Warwickshire, placing them back in title contention. Sussex, while remaining unbeaten, could only manage a draw with Surrey. The contest between Nottinghamshire and Derbyshire also ended in a high-scoring draw. Somerset achieved their first win of the season away at fellow relegation candidates Derbyshire, while Surrey managed a fourth successive draw, this time against title contenders Yorkshire. A draw for Sussex against Nottinghamshire was enough to give them second place in the table, eight points behind Yorkshire, and 8.5 ahead of Durham, at the halfway stage of the season.