Since the U.S. has only ever had five native-born men break 2:10 on an unaided course I was curious how things looked for some of the other top marathon nations' top five with the same criteria. Additions/corrections welcome.
U.S.A.
2:06:17 - Ryan Hall London 2008
2:09:32 - David Morris Chicago 1999
2:09:35 - Jerry Lawson Chicago 1997
2:09:38 - Ken Martin New York 1989
2:09:41 - Alan Culpepper Chicago 2002
Kenya
2:03:38 - Patrick Makau Berlin 2011
2:03:42 - Wilson Kipsang Frankfurt 2011
2:04:27 - Duncan Kibet Rotterdam 2009
2:04:27 - James Kwambai Rotterdam 2009
2:04:40 - Emmanuel Mutai London 2011
Ethiopia
2:03:59 - Haile Gebrselassie Berlin 2008
2:05:18 - Tsegaye Kebede Fukuoka 2009
2:05:23 - Lelisa Feyisa Rotterdam 2010
2:05:25 - Bazu Worku Berlin 2010
2:05:44 - Getu Feleke Amsterdam 2010
Morocco
2:05:27 - Jaouad Gharib London 2009
2:05:30 - Abderrahim Goumri London 2008
2:05:38 - Khalid Khannouchi London 2002 (changed to US citizenship)
2:06:46 - Abdelkader El Mouaziz Chicago 2002
2:06:48 - Rachid Kisri Paris 2009
Japan
2:06:16 - Toshinari Takaoka Chicago 2002
2:06:51 - Atsushi Fujita Fukuoka 2000
2:06:57 - Takayuki Inubushi Berlin 1999
2:07:13 - Atsushi Sato Fukuoka 2007
2:07:35 - Taisuke Kodama Beijing 1986
Spain
2:06:52 - Julio Rey Hamburg 2006
2:07:23 - Fabian Roncero Rotterdam 1999
2:07:34 - Antonio Pena Lake Biwa 2001
2:07:42 - Jose Rios Lake Biwa 2004
2:07:48 - Francisco Javier Cortes Hamburg 2001
South Korea
2:07:20 - Lee Bong Ju Tokyo 2000
2:07:49 - Kim Yi Yong Rotterdam 1999
2:08:30 - Ji Young Joon Daegu 2009
2:08:47 - Hwang Young Cho Beppu-Oita 1992
2:08:49 - Baek Seung Do Tokyo 2000
Italy
2:07:22 - Stefano Baldini London 2006
2:07:52 - Giacome Leone Lake Biwa 2001
2:08:02 - Albercio Di Cecco Rome 2005
2:08:33 - Danilo Goffi Rotterdam 1998
2:08:49 - Francesco Ingargiola Roma 2000
And for comparison, foreign-born Americans
2:05:38 - Khalid Khannouchi London 2002
2:08:56 - Abdi Abdirahman Chicago 2006
2:09:13 - Meb Keflezighi New York 2011
2:09:21 - Alberto Salazar Fukuoka 1983
(who is the fifth?)
I don't have time to look up Brazil, Eritrea, Portugal, South Africa etc. Interesting to compare the different countries, though.