Which grounds have the largest and the smallest pitches in the English Football League?

Manchester City (Maine Road) has the largest pitch in the league at 107 metres by 73 metres (approximately). HalifaxTown (The Shay) and Swansea City (Vetch Field) have the smallest pitches in the league at 100 metres by 64 metres.
[From dfes.gov.uk 2004 article, no longer online]

Over the last few years the Premier League has moved to standardize the size of pitches. Currently, ten clubs have sized their pitches at 105m x 68m; Queens Park Rangers has the smallest at 100m x 65.86m.

http://www.dailymail.co.uk/sport/football/article-3031824/Stoke-boss-Mark-Hughes-extended-Britannia-Stadium-pitch-largest-playing-area-Premier-League.html

The largest pitch in the English Football League (72 clubs) is Leyton Orient at 9200 sq yds and the smallest is Crewe Alexandra and Wigan Athletic at 6600 sq yds.

115 x 80 9200 Leyton Orient
115 x 78 8970 Nottingham Forest
117 x 76 8892 Leeds United
115 x 77 8855 Shrewsbury Town
114 x 77 8778 Port Vale
115 x 76 8740 Blackburn Rovers, Huddersfield Town
112 x 78 8736 Oxford United
113 x 77 8701 Hartlepool United
114 x 76 8664 Rochdale, Notts County
115 x 75 8625 Birmingham City, Brighton & Hove Albion, Bristol City, Sheffield Wednesday, Wycombe Wanderers
116 x 74 8584 Wolverhampton Wanderers
114 x 75 8550 Gilligham
112 x 76 8512 Peterborough United
115 x 74 8510 Milton Keynes Dons, Coventry City
110 x 77 8470 Preston North End
114 x 74 8436 Norwich City , Newcastle United
115 x 73 8395 Portmouth
110 x 76 8360 Morecambe
116 x 72 8352 Northampton Town
111 x 75 8325 Grimsby Town
114 x 73 8322 Exeter City
112 x 74 8288 Fleetwood Town, Blackpool, Carlisle United
115 x 72 8280 Aston Villa, Yeovil Town
110 x 75 8250 Barnsley, Cardiff City, Wimbledon,
109 x 76 8284 Doncaster Rovers
112 x 73 8176 Bury, Charlton Athletic, Plymouth Argyle
110 x 74 8140 Southend United, Cambridge United
111 x 73 8103 Scunthorpe United
112 x 72 8064 Sheffield United, Newport County, Queens Park Rangers, Newport County
110 x 73 8030 Brentford, Bristol Rovers, Walsall
111 x 72 7992 Accrington Stanley, Cheltenham Town
111 x 72 7990 Barnet (102m x 65.5m)
114 x 70 7980 Mansfield Town
110 x 72 7920 Crawley Town, Burton Albion, Rotherham United, Luton Town
113 x 70 7910 Bradford City
111 x 71 7881 Chesterfield,
112 x 70 7840 Ipswich Town
109 x 71 7739 Fulham
110 x 70 7700 Swindon Town, Colchester United, Stevenage
106 x 72 7632 Oldham Athletic
105 x 68 7140 Millwall, Derby County, Bolton Wanderers
102 x 70 7140 Reading
110 x 60 6600 Wigan Athletic
100 x 66 6600 Crewe Alexandra

Click on the name of each club on this website to see the pitch size (first column), which is a total of 72 clicks, lol. The sq yds area in the second column is a calculated figure.
http://www.footballgroundguide.com/
The data for Mansfield Town is from this webpage, as it's blank at footballgroundguide.com
http://www.stevesfootballstats.co.uk/mansfield_town_club_record.html