A tetromino's spawn location is the place where it enters the playfield. The specific locations vary across different rotation systems, although they share the common characteristic of being between rows 20-24 and columns 4-7. Tetris guideline games in particular have two invisible rows above row 20 where the active tetromino spawns.

Guideline SRS

Locations

Spawn locations in more recent guideline games

In the more recent guideline games such as Tetris Friends, the game first tries to spawn tetrominos in rows 20-21. If it fails then the game tries rows 21-22 like in older guideline games. If both attempts fail then the game ends.

For example, in this playfield all pieces except I spawn in rows 20-21 (shown in the outline), but I spawns in rows 21-22 (outside of the screen):