Akatsuka District (赤塚台) is the city seen in the 1988 series of Osomatsu-kun, as well as the name being given for the location in Comic BomBom's "Burst of Laughter World-zansu" guide in the same year.
The cast live here and most of the antics take place in the location, though there may sometimes also be different locations they are set as living in for an episode, or there may be alternative takes on "Akatsuka" itself.
In the original run of manga, there was no specific name or identity given for the place that the Matsunos lived, though the 1980s Kodansha relaunch would place them in the actual district of Shimo-ochiai, located in Shinjuku Ward. This was likely to closely align to the Fujio Pro location being in nearby Naka-ochiai and that being the decided setting of The Genius Bakabon.
In the actual world, there is a district by the name of "Akatsuka" in Tokyo, but located in Itabashi Ward
Akatsuka District Train Station
The first location seen in the series, where Iyami's train comes in and where Matsuzo commutes to and from work. It is also seen when Chibita tries to see Jajako off in episode 61.
Though the name clearly comes from Akatsuka himself, there are those that wonder if it should be seen as equivalent to Itabashi's very Shimo-Akatsuka station, down to the old-fashioned Tobu electric-style commuter trains (including one line that continued to be in usage up until 2018).
Located in 3-chome (3丁目, third city district). A two-story house fashioned after those that were popularized in the late 1950s (Showa 30s). This is where events surrounding the family take place the most. The style of this house was imported back to the tie-in manga around this period, and would also serve as the loose basis for the house seen in Osomatsu-san.
A laboratory seen in settings where Dekapan is a scientist for the plot. It is modeled after his own head.
The neighborhood koban where The Police Officer with the Connected Eyes is seen to work, as well as a later officer or any others that may be utilized for a plot's needs.
A standard tall white Japanese school building, first seen in episode 7 but popping up in any other school settings as needed. The sextuplets, Totoko, and sometimes Hatabou and Chibita are shown to attend classes here.
In the manga, elementary schools that were shown in the town had generic placeholder names of "XX Elementary" or "OO Elementary".
A set of pipes seen in episode 1 and on other occasions, that are situated out in an empty lot. As seen in their initial appearance, a cable antenna and exhaust pipe appear to be set up on them even though there is no actual TV for him to watch inside.
Its appearance and location may vary depending on the plot, but there are points where it is commonly seen to be some type of shack near a river and modeled after his own face. It is a rather shabby place, complete with mushrooms and filth growing about inside.
In the Burst of Laughter World-zansu guide, the house seen there is a more modern two-story house modeled after his face.
Only existing in the settings of episode 19 and the Watermelon Planet movie, but also somewhat reflected in the Burst of Laughter World-zansu guide. It is a fairly large, Japanese mansion-styled home and her own parents dress in rich, attractive fashion.
Seen in some later episodes of the series where a larger city area is needed for a plot. This is where all the department stores and entertainment tend to be.