In 1800, the population of the region making up present-day Croatia was just over 1.2 million. Croatia's population grew relatively consistently throughout the 19th and early 20th centuries, despite the region suffering around 200,000 fatalities in each of the World Wars. The lack of clearly defined boundaries, mass displacement and general disorganization have made it very difficult for historians to estimate the total number of fatalities suffered by Croatia and by ethnic Croats in this time; additionally, the various ethnic groups within Yugoslavia at the time committed a number of atrocities against one another, which has exacerbated this.

In spite of these events, the population of Croatia would continue to grow steadily until the early 1990s, when it was one of six parts of the Socialist Federative Republic of Yugoslavia. In the wake of communism's demise in Southern Europe in the late 20th century, Croatia claimed its sovereignty in 1991, which set in motion the Croatian War of Independence with Serbia. War was waged for four years, and saw the deaths of more than 20,000 people, while several hundred thousand were displaced. In the quarter century since the war's end, Croatia has emerged as a high-income, developing country, with a booming tourism and hospitality industry. However the population has continued to drop as a result of declining birth rates, and large-scale economic migration (particularly influenced by the financial crisis of 2008 and Croatia's accession to the European Union in 2013).

Bosnia and Herzegovina's total population grew at quite a steady rate from the early nineteenth century until the mid-1900s, increasing from 852,000 people in 1818 to 2.7 million in 1950. Following the Second World War, the population grew at an even faster rate, reaching 4.5 million people by the end of the 1980s. Throughout this period, Bosnia and Herzegovina was never an independent country, as it belonged to the Ottoman Empire until 1875, before it was then annexed by Austria-Hungary until the First World War, after which it became a part of Yugoslavia. During this time, ethnic Bosnians (the majority of which were Muslim) often faced oppression and persecution, and even mass genocide during the Second World War (when it was briefly annexed by Croatia, which was a puppet state of Nazi Germany). The Bosnian War From 1989 onwards, Bosnia's population decreased drastically, by approximately 750,000 people by the end of the century. This sudden change coincides with the dissolution of Yugoslavia, where the country experienced economic instability in the 1980s and then the independence of its internal states in the early 90s; Bosnia and Herzegovina itself became independent in 1992. The formation of an independent state lead to civil unrest among the different ethnic groups within Bosnia and Herzegovina, resulting in the Bosnian War that caused the deaths of approximately 100 thousand people, as well as the displacement of over 2.2 million. Modern Bosnia and Herzegovina Since this period in Bosnia and Herzegovina's history the population has never recovered, and a further decline in the past decade has seen the population fall below 3.3 million people in 2020; which is a decrease of more than one million people since the war. As the country seemingly comes to terms with its difficult past, and deals with high unemployment and ethnic tensions; there are some indicators for a brighter outlook for Bosnia and Herzegovina's future. Today, Bosnia and Herzegovina is seen as a developing country and economy, it is an applicant for both EU and NATO membership, and an emerging tourism sector may provide much-needed employment across the country.