-Primary source for attendance figures on map … soccerway.com.
Secondary sources… european-football-statistics.co.uk, worldfootball.net, ligue1.com.

The map and the chart…
The map shows all clubs in Europe which drew above 25 000 per game in 2015-16 (75 teams). Each club’s crest is placed on the location-map of Europe, and at the far right is a chart which shows national flag, club crest, attendance-rank [in Europe], and 2015-16 home average attendance.

If a club on the map was not in the country’s first division in 2015-16 (ie, not in the 1st level), that is noted on the chart…there were 9 second-tier clubs that drew above 25 K last season, and there was one third-tier club that drew above 25 K last season (Dynamo Dresden). Also noted is any promotion/relegation in 2015-16…and of these 75 clubs on the map, 13 of these clubs will be in the second-tier in 2016-17. In other words, a rather surprising 17% of all European football clubs which drew above 25 K in 2015-16 will be in the second division in 2016-17.

Clubs that just missed out on being on this map are 3 English clubs…Crystal Palace, West Bromwich, and Middlesbrough – all 3 of whom drew in the high 24-K-range.

Below is an illustration showing a stadium-photo of each of the twelve highest-drawing clubs in Europe in 2015-16 (all teams which had an average crowd-size of 50 000 or more). Highest-drawing club, yet again (for the 5th straight season), is Germany’s Borussia Dortmund, who drew 81.1 K in their 81.3-K-capacity Westfalenstadion (aka Signal Iduna Park), in Dortmund, which is in the Rhine-Ruhr region of west-central Germany. Of the 12 clubs which drew above 50 K in 2015-16, 6 are German clubs (Dortmund, Bayern, Schalke, Hamburg, Stuttgart, ‘Gladbach), 3 are English clubs (Man Utd, Arsenal, Man City), 2 are Spanish clubs (Barça and Real ), and one is a Portuguese club (Benfica). All 12 of these clubs were top flight clubs in 2015-16, but next season one of them – Stuttgart – will be in the 2nd division (in 2-Bundesliga). And speaking of high-drawing clubs that were recently relegated…just missing out at 50-K-per-game last season were 3 clubs, including the once-again-relegated Newcastle Utd of England (at 49.7 K per game). Also just missing out on 50 K per game last season were Hertha Berlin of Germany (also at 49.7 K), and Ajax of the Netherlands (at 49.2 K).

Below – Highest-drawing football clubs in Europe (UEFA) – Top twelve highest-drawing clubs, 2015-16: All clubs which drew over 50 000 per game…
(from home, domestic league matches in 2015-16).

1. Borussia Dortmund/ Signal Iduna Park (aka Westfalenstadion), 81 178.
2. FC Barcelona/ Camp Nou, 78 251.
3. Manchester United/ Old Trafford, 75 286.
4. Bayern Munich/ Allianz Arena, 75 000.
5. Real Madrid CF/ Santiago Bernabéu, 67 698.
6. FC Schalke 04/ Veltins Arena, 61 386.
7. Arsenal/ Emirates Stadium, 59 944.
8. Manchester City/ Etihad Stadium (aka City of Manchester Stadium), 54 041.
9. Hamburger SV/ Volksparstadion, 53 700.
10. VfB Stuttgart/ Mercedes-Benz Arena, 51 983.
11. Borussia Mönchengladbach/ Stadion im Borussia-Park, 51 715.
12. SL Benfica/ Estádio da Luz, 50 322.


Photo credits above –
1. Dortmund, Suedtribune (South Terrace) at Westfalenstadion, photo by Christopher Neundorf at Datei:Südtribüne Dortmund.jpg (de.wikipedia.org).
2. Barcelona, tifo at Camp Nou, photo unattributed at deportesrcn.com.
3. Manchester United, full house at Old Trafford (yet again, but maybe not for long/see rest of this sentence…), photo by Getty Images via metro.co.uk/2016/02/04/manchester-united-to-close-part-old-trafford-due-to-drab-ticket-sales.
4. Bayern Munich, tifo at Allianz Arena, photo unattributed at ecofoot.fr.
5. Real Madrid, photo of interior of Santiago Bernebeu Stadium prior to tifo [April 2013], photo by Luisao200 at File:Real Madrid fans at Santiago Bernabeu between the chreography vs. Bor. Dortmund.JPG (commons.wikimedia.org).
6. Schalke 04, photo of fans with flags and banners in Veltins-Arena, photo by FC Schalke 04 at schalke04.de/[stadion-und-tickets/ticketshop].
7. Arsenal, photo of interior of Emirates Stadium unattributed at anajovanovicai.wordpress.com.
8. Manchester City, photo showing 2015 Etihad Stadium expansion [Aug. 2015], photo by Higor Douglas at File:Etihad Stadium – Man City vs Chelsea 2015-16 (2).jpg.
9. Hamburger SV, tifo at Volkparkstadion, photo by Witters via hamburg-zwei.de/2014/Oktober/Aenderungen-beim-HSV-Shuttle-HSV-Hoffenheim-So-kommt-Ihr-zum-Stadion.
10. VfB Stuttgart, photo of fans with flags and banners in the Canstatter Kurve, photo by RudolfSimon at File:Cannstatter Kurve 2013.JPG
11. Borussia Mönchengladbach, screenshot of youtube video, image from Borussia Mönchengladbach vs Manchester City [Oct. 2015] (youtube,com video uploaded by vflman).
12. Benfica, photo by estadio11.blogspot.com/2011_02_01_archive.
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Blank map: Thanks to Roke at File:BlankMap-Europe-v4.png (commons.wikimedia.org).

Thanks to Soccerway for attendance figures.