This is the only episode to actually be filmed in Seattle.
"The 1000th Show" was filmed on location in Seattle, Washington, on the real Frasier Crane Day--September 11, 1997. Seattle locations were featured prominently in the show--the Space Needle, the Monorail and the Monorail Station, and Pike Place Market, where Niles (David Hyde Pierce) is almost hit with a fish when Frasier (Kelsey Grammer) and he walk into the middle of the Market's famous fish-throwing tradition.
In the middle of this episode--when Frasier (Kelsey Grammer) and Niles (David Hyde Pierce) are leaving the shoe store-- the sign for the store is labeled "Lloyd & Keenan Company", which is a reference to executive producer Christopher Lloyd and co-executive producer Joe Keenan.
Martin compliments Niles on being the last name in the magazine article, noting "the way they saved you for last so you really stand out." John Mahoney, who played Martin, is always the last cast member named in the opening credits.
Per the title, Frasier Crane's (Kelsey Grammer) 1000th radio broadcast is also the 100th episode of the series "Frasier (1993)."