The original theatrical film shorts released from 1922 - 1944
were titled "Hal Roach's Rascals"; another name Roach tried
during the silent years from 1922 - 1928 was "The Terrible Ten";
But since the first short was titled "Our Gang", the public
began to refer to them as "'Our Gang' Comedies"; so Roach
finally adopted that name for this series of shorts; and by
the sound era (circa 1928) "Our Gang" was the official name;
The first Little Rascals "talkie" was "Schools Out" (1928);
Quite a few child actors were used for years until they
began to get too old, at which time they were unceremoniously
replaced by a fresh face; Several TV actors got their start
working in this series including Jackie Cooper (1929-1931),
Robert Blake known as "Mickie" (1939-1944) and West-coast
local TV children's show host Johnny Downs (1925 - 1927);
But perhaps the best-known was Carl "Alfalfa" Switzer, who
was only involved in the series for five years (1935-1940.)
Another memorable character was "Buckwheat", played by
young Billie Thomas who was there for the final ten years
of production (from 1934-1944.) And the series also featured
the little boy known as "Spanky" played by George McFarland
(from 1932-1942.) A rock vocal group during the hippie 1960's
used the name "Spanky & Our Gang", although there was no
connection to the Hal Roach films.
It is said that Hal Roach got the idea for the comedies that
revealed the world as seen from a child's point of view when
he heard through his office window a conversation between some
children in a lot next door arguing over discarded scraps of
wood they were trying to split up for salvage;
The shorts were filmed at the Hal Roach Studios in Culver
City, a Los Angeles suburb; and exteriors at the Arnaz Ranch
near what is now Robertson Blvd. in Hollywood;
MGM bought Hal Roach in 1938, and some "Our Gang" fans say
the quality of stories and production started to decline
at that point, when they became more "slickly produced."
The final three episodes were released in 1944. They were
"Radio Bugs", "Dancing Romero" and "Tale of a Dog."
Giving a little more specific information on the excellent post above, the Hal Roach Studios were located on the east side of Washington Blvd in Culver City. Landmark Street runs through what used to be the heart of the old studio lot.
The "Roach Ranch" where many of the exterior scenes were filmed (i.e. the schoolhouse seen in the Our Gang films Teacher's Pet, Readin and Writin, etc), was located about a mile northwest of the studio. Today, the Roach Ranch is part of the Beverlywood housing development. The ranch was roughly within the boundaries of these contemporary streets: David Avenue on the north, Canfield Avenue on the east, South Beverly Drive on the west and Beverly Street on the south.
I hate to rain on anyone's parade, but Landmark Ave. ran along the edge of the main stido, no through it. I have a map (produced for insurance purposes) that shows across Landmark Ave. was the Pacific Military School. Prior to that it was another studio (Lehrman Studio home of L-Kho comedies in the late teens).
I have many pictures of the lot, and everyone shows the studio as long and narrow with stages flanking a narrow street running through it. Landmark ran to the outside of these rows of stages.
Yes, up until the studio expanded (in the late 1930s), Landmark (today) marks the southern boundary. However, the studio did a major expansion to the south late in the 1930s and so, at that time, right up until its demolition in 1963, the area both to the north and south of Landmark were a part of the studio.
It's actually very easy to see exactly where the studio was by looking at any contemporary aerial shot (google / bing / etc) as you can see the large industrial buildings north and south of Landmark, making the footprint of the studio lot easy to see.