Alongside ‘wilderness’ the category ‘national park’ is one of the most powerful within nature conservation. How a category, such as national park including its inherent components, is understood and valued differ between social actors across space and time. This paper aims to look critically at how categories are used and understood by stakeholders with different land-use interests in the southern mountains of Jämtland County, Sweden, specifically in relation to a suggested new national park. Data has been collected through in-depth interviews,surveys, discourse analysis and observations. Results show how our need to use categories, such as ‘nature reserve’, ‘wilderness’ and ‘local community’, at the same time can create problems. For example, the proposed national park is perceived differentlyby different stakeholders, there exists mistrust between them, and the park is contested for several reasons. Categories create paradoxes that lead to tension and conflict, and they often act to block change in both thinking and practice. These effects can occur when a piece of land belongs to different categories, when a category remains static while the local context changes, when the material and immaterial ‘components inherent in landscapes are categorised differently by different users, and when the same category is attributed different values. A lack of awareness of this impedes novel solutions and potential relevant trade-offs. A critical analysis of how categories are formed, by whom, and their effects, are important for understanding and moving beyond conflicts in conservation.