The small blue is known for being the smallest butterfly found in the United Kingdom. It has a very patchy distribution across the UK with its strongholds on the chalk and limestone grasslands of southern England such as the Cotswolds and Salisbury Plain. Across the rest of Britain and Ireland it is often associated with coastal habitats with widely scattered colonies in northern England and the far north of Scotland. It is a Priority Species for conservation in Northern Ireland and under the UK Biodiversity Action Plan.