In its proclaimed borders, Herzeg-Bosnia encompassed about 30% of the country, but did not have effective control over the entire territory as parts of it were lost to the Army of Republika Srpska (VRS) at the beginning of the Bosnian War.

The armed forces of Herzeg-Bosnia, the Croatian Defence Council (HVO), were formed on 8 April 1992 and initially fought in an alliance with the Army of the Republic of Bosnia and Herzegovina.

The term Herzeg-Bosnia (Croatian: Herceg-Bosna) appeared in the late 19th century and was used as a synonym for Bosnia and Herzegovina without political connotations.

One of the earliest mentions of the term was by Croatian writer Ivan Zovko in his 1899 book Croatianhood in the Tradition and Customs of Herzeg-Bosnia.

In the first half of the 20th century the name Herzeg-Bosnia was used by historians such as Hamdija Kreševljaković and Dominik Mandić and Croatian politicians Vladko Maček and Mladen Lorković.

Alija Izetbegović proposed an asymmetrical federation on 22 February, where Slovenia and Croatia would maintain loose ties with the 4 remaining republics.

[7][8] On 6 June, Izetbegović and Macedonian president Kiro Gligorov proposed a weak confederation between Croatia, Slovenia and a federation of the other four republics, which was rejected by Milošević.

[11][12] From July 1991 to January 1992, during the Croatian War of Independence, the JNA and Serb paramilitaries used Bosnian territory to wage attacks on Croatia.

[17][18] In October 1991 the Croat village of Ravno in Herzegovina was attacked and destroyed by Yugoslav People's Army (JNA) forces before turning south towards the besieged Dubrovnik.

[22] On 18 November, the autonomous Croatian Community of Herzeg-Bosnia (HZ-HB) was established, it claimed it had no secession goal and that it would serve a "legal basis for local self-administration".

[25] One of Boban's advisers stated that Herzeg-Bosnia was only a temporary measure and that the entire area will in the end be an integral part of Bosnia and Herzegovina.

[27] At a session of the Supreme State Council of Croatia, Tuđman said that the establishment of Herzeg-Bosnia was not a decision to separate from Bosnia and Herzegovina.

"[30] He based this on the belief that the Serbs did not accept Bosnia and Herzegovina and that Bosnian representatives did not believe in it and wished to remain in Yugoslavia,[31] and thought that such a policy would avoid war.

[32] Tuđman declared "it is time that we take the opportunity to gather the Croatian people inside the widest possible borders".

[34] The referendum question was: "Are you in favor of a sovereign and independent Bosnia-Herzegovina, a state of equal citizens and nations of Muslims, Serbs, Croats and others who live in it?

[37] The legal rationale for the formation of HVO was seen in the laws of Yugoslavia that allowed citizens to organize their own self-defence when their government was unable or unwilling to defend them.

Boban said that the HVO was formed because "thirteen Croatian villages in the municipality of Trebinje – including Ravno – were destroyed and the Bosnian government did nothing thereafter".

In late May, the HVO launched a counter-offensive and, after more than a month of fighting, managed to suppress the VRS forces from Mostar and the surrounding area.

In late July 1993 the Owen-Stoltenberg Plan was proposed by U.N. mediators Thorvald Stoltenberg and David Owen that would organize Bosnia and Herzegovina into a union of three ethnic republics.

[51] On 26 February 1994 talks began in Washington, D.C. between the Bosnian government leaders and Mate Granić, Croatian Minister of Foreign Affairs to discuss the possibilities of a permanent ceasefire and a confederation of Bosniak and Croat regions.

Under this agreement, the combined territory held by the Croat and Bosnian government forces was divided into ten autonomous cantons.

[52] In November 1995 the Dayton Agreement was signed by presidents of Croatia, Bosnia and Herzegovina and Serbia that ended the Bosnian war.

[57] An Army of the Federation of Bosnia and Herzegovina was to be created by merging units from the ARBiH and the HVO, though this process was largely ineffective.

[62] According to a 1999 report by the European Stability Initiative (ESI), Herzeg-Bosnia structures continued to function and a parallel government acted to expand the independence of its financial institutions.

[68] This maximalist approach was done for a better position during negotiations, which would inevitably reduce the excessive demands to an optimal envision of a Croat unit.

[71] The arrival of Bosniak refugees from areas captured by the VRS to HVO-controlled parts of central Bosnia and Mostar altered the ethnic structure and reduced the share of Croats.

Each district of Herzeg-Bosnia was responsible for its own defence until the formation of four Operative Zones with headquarters in Mostar, Tomislavgrad, Vitez and Orašje.

[85] The HVO forces became better organized as time passed by, but they started creating guards brigades, mobile units of professional soldiers, only in early 1994.

He claimed the two-entity system is untenable and that Croats have been subject to assimilation and deprived of basic rights in the federation with Bosniaks.

"[98] In 2013, six political and military leaders of Herzeg-Bosnia, Jadranko Prlić, Bruno Stojić, Slobodan Praljak, Milivoj Petković, Valentin Ćorić, and Berislav Pušić, were convicted in a first instance verdict by the ICTY for being part of a joint criminal enterprise (JCE) against the non-Croat population of Bosnia and Herzegovina.