Headquarters (also known as King of the Hill) is a multiplayer game mode featured in all Call of Duty games until (and including) Call of Duty: Black Ops II. In this mode, teams capture a set point in the map (the "headquarters") to gain points. It is one of the most popular game modes, as it offers experience per time that the headquarters is held, allowing for larger sums of points earned. Teams must coordinate a steadfast and solid defensive perimeter around a captured headquarters in order to hold it. In Call of Duty 4: Modern Warfare, Call of Duty: Modern Warfare 2, and Call of Duty: Black Ops the headquarters is marked by a metal box with a computer on top (The Wii version has a wooden box with a Satchel charge); each game using slightly different representations. In Call of Duty: World at War a wooden table with a radio and helmet is used.
There is also a Hardcore variant. Modern Warfare 3 features the mode with the "Ricochet" option on.
In order to capture the headquarters location, at least one player from a team must stay within a close proximity of the location; more players accelerate how fast the location is captured. Once a headquarters is captured, the defending team may not respawn. Modern Warfare 2, Modern Warfare 3 and Black Ops feature activation delays, allowing each team to attempt to gain hold of the location before the headquarters may be captured for points.
The Headquarters game mode in Modern Warfare 2 is somewhat modified from its predecessors. In HQ Pro, the Headquarters' location is marked but remains inactive for thirty seconds before it can be captured, giving both teams a fair chance to get into position. This was done to address the problems in the previous games, where oftentimes the team that captured the first Headquarters would win the game, given each HQ location after it is where they respawn. Additionally, the goal score is 200 instead of 250 in previous games. Also, once defending teammates are eliminated, they no longer score XP for themselves.
A Hardcore Ricochet mode is available for HQ; despite it being hardcore players respawn immediately (as long as they are not defending an HQ). If teammates are shot, the player takes the damage or dies, depending on the team damage inflicted.
Headquarters Pro is similar to Modern Warfare 2 in Modern Warfare 3, except that the goal score is 400 instead of 250.