For me, it's always interesting to see portrayal of Western countries in Asian media. Here's a list of manga in different genres and demographics that are set in or feature Western countries as important part of the plot. I was focusing on modern-ish times(70s onwards), so historical manga will be omitted.
Note: arranged in the order of release. Some of the titles are NSFW.
Work in progress!
Manga, 3 vol, 1970
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Manga, 21 vol, 1976
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Manga, 8 vol, 1978
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Manga, 3 vol, 1980
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Manga, 6 vol, 1984
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Manga, 19 vol, 1985
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Manga, 1 vol, 1985
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Manga, 1 vol, 1986
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Manga, 13 vol, 1990
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Manga, 1 vol, 1991
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Manga, 17 vol, 1992
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Author:8
Manga, 1 vol, 1989
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Manga, 17 vol, 1990
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Manga, 7 vol, 1993
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Author:8
Manga, 18 vol, 1994
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Manga, 1 vol, 1994
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Manga, 4 vol, 1995
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Manga, 11 vol, 1997
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Manga, 17 vol, 1999
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Manga, 34 vol, 2000
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Manhwa, 7 vol, 2000
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Manga, 25 vol, 2001
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Manga, 8 vol, 2003
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Manga, 1 vol, 2003
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Manga, 1 vol, 2004
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Manga, 2 vol, 2006
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Manga, 10 vol, 2005
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Manga, ? vol, 2007
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Manga, 20 vol, 2008
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Manga, 2 vol, 2008
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Manga, 6 vol, 2008
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Manga, 4 vol, 2011
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Manga, ? vol, 2012
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Author:9
Manga, 7 vol, 2012
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Manga, 1 vol, 2013
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Manga, 6 vol, 2013
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Manga, 1 vol, 2015
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Manga, 1 vol, 2016
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Author:8
Manga, 1 vol, 2016
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Author:8
Manga, ? vol, 2016
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Author:8
Manga, 1 vol, 2017
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Author:9
Manga, 2 vol, 2019
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Author:9
Manga, 1 vol, 2017
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Author:8
Manga, ? vol, 2019
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Manga, ? vol, 2019
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Manga, ? vol, 2019
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Light Novel, 1 vol, 2021
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Manga, 3 vol, 2020
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Author:9
Manga, 1 vol, 2020
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Author:6