This dataset consists of stock (length) data for linear features across Great Britain in 1998 in a vector format. The data are national estimates generated by analysing the sample data from 569 1km squares surveyed for the Countryside Survey long term monitoring project, then scaling up to a national level. The data are presented as mean lengths per 1km square for seven different feature categories within 45 different land class types, based on the ITE Land Classification. The Countryside Survey is a unique study or 'audit' of the natural resources of the UK's countryside, carried out by the Centre for Ecology & Hydrology. The sample sites are chosen from a stratified random sample, based on a 15 by 15 km grid of GB. Surveys have been carried out in 1978, 1984, 1990, 1998 and 2007 with repeated visits to the majority of squares. The countryside is sampled and surveyed using rigorous scientific methods, allowing us to compare new results with those from previous surveys. In this way we can detect the gradual and subtle changes that occur in the UK's countryside over time. In addition to linear features, habitat areas, species plot, soil plot, freshwater habitat and satellite map data are also produced by Countryside Survey. Full details about this dataset can be found at https://doi.org/10.5285/6bc0ccb4-63c8-4121-bc4b-3c479877cff9