Pipeline is a gloomy setting centered around an abandoned rail yard in Ukraine, with a large extent of overgrown grassland. There are two large warehouses in the center of the map which often sees the main concentration of fighting. The north warehouse has a small room players can hide in and ladders leading to a catwalk which grants access to the roof. The south warehouse has a u-shaped upper level looking over the ground floor and office rooms. Additionally there is a entrance to an underground tunnel. This tunnel leads to the north-west and north-east sections of the map.
This map's layout supports a variety of play-styles, with the warehouses and tunnel encouraging frantic close-quarters action and the surrounding areas supporting mid to long-range action.
In Call of Duty 2, one of the early missions involves the player crawling through a pipe at the beginning of the level. When they crawl through completely, they end up in what appears to be Warehouse 2 of this map. It is almost identical, with the small passageway that runs under the whole level present in the Call of Duty 2 version. The same warehouse-building returned even in Modern Warfare 3 in the single player mission "Back on the Grid" and the Spec-Ops mission "Fatal Extraction", although slightly modified.