Marine crannogs are archaeological remains distributed around the Scottish coastline.T he two groupso f sites discussedin this thesisa re located in the intertidal zone of the upper reaches of the Firth of Clyde and the Beauly Firth. As a result of their wet surroundingst hey have beena ssociatedw ith freshwaterc rannogsa lthough little is known of their origins, function and structural design. Evidence from early investigations has indicated that substantial remains are preserved beneath the intertidal deposits. Intertidal fieldwork techniques have been developed in this thesis to enable these sites to be surveyed, investigated and to sample some of the archaeologya nd palacoenvironmentael videncep reservedo n them. Evidence from previous investigations of these sites is used to re-locate them and survey was undertaken to identify additional sites. The results from the surveys of the existing marine crannogs are used to indicate the variety of locations, types of remains and other characteristics of these sites. On the basis of these results, one site was chosen for additional research. Sampling and excavation on the focus site indicates primary and subsequent structural remains and particular sedimentary and artefactual characteristics. Some of the remains sampled are subjected to multispectral analysis, the results of which indicate that palaeoenvironmental indicators arc found in marine crannog deposits and can be used to establish conditions when the location was occupied and the site constructed. An example of the palaeoenvironmcntal indicators analysed was diatoms, which are helpful when investigating the position and salinity levels of contemporary water levels. Results from the surveys and sample analysis arc used to indicate that marine crannogs are a distinct sub-group of crannogs and that the two groups display a regional diversity of both structures and chronology. The identification of a distinct range of structures from Iron Age Scotland contributes to the diversity of sites from this period.