<![CDATA[Berau Regency is one of the districts in East Kalimantan Province that has experienced an acceleration in population growth in the last decade, in line with its position as a buffer area for the Capital City of the archipelago (IKN). This article aims to analyse the population dynamics of Berau Regency and its implications for the sustainable development agenda towards 2045. The research uses a descriptive-quantitative approach based on secondary data from the Central Statistics Agency (BPS) of Berau Regency, One Data of Berau Regency, and SINTA-indexed scientific literature in 2023–2026. The results show that the population of Berau has increased from 248,035 people (2020 Population Census) to 288,943 people (BPS 2024 projection), with a population growth rate (CAGR) that accelerated from 2.19 per cent (2014–2019) to 4.46 per cent (2019–2024). The age structure of the population in 2024 is dominated by the productive age (67.01%), indicating that the demographic bonus window has not been fully utilised, reflected in the Open Unemployment Rate (TPT), which has actually risen to 5.15 per cent. Berau's Human Development Index (HDI) will reach 77.17 in 2024, in the high category, but still 1.62 points below the average of East Kalimantan Province. The author's three projected scenarios produce an estimated population in 2045 in the range of 455 thousand to 722 thousand people, while other literature projects a surge of up to 1.5 million people in 2044 due to inbound migration related to IKN. This article recommends strengthening population data governance, investment in education and job skills, anticipatory spatial planning, and mitigation of post-mining environmental risks so that Berau's population growth becomes a capital for sustainable development, not a burden.]]>
