Records of the River Plate Trust Loan and Agency Company Ltd, 1876-1978, including minutes, ledgers, registers, accounts, annual reports, legal documents, insurance records, staff records, letters and files, some relating to subordinate companies (Ref: A); and records of the subsidiary companies it administered:
River Plate and General Investment Company Ltd, comprising minutes, 1888-1965, ledgers, 1888-1941, and annual reports, 1889-1983 (Ref: B);
Mortgage Company of the River Plate Ltd, comprising minutes, 1888-1965, ledgers, 1888-1953, and annual reports, 1888-1981 (Ref: C);
Compagnie Française des Chemins de Fer de la Province de Santa Fé, comprising circulars to bondholders, 1891-1947, and reports, 1936-1947 (Ref: D);
London Trust Company, comprising ledgers, 1889-1928, registers of stock, 1889-1958, and miscellaneous papers, 1819-1974 (Ref: E);
Entre Rios Railway Company, comprising reports, 1891-1900, and circulars and minutes, 1933-1947 (Ref: F);
Cucuta Railway Company, comprising Presidents' reports, 1926-1936 (Ref: G);
Montevideo Waterworks, comprising reports and accounts, 1880-1940, and notices and circulars, 1949-1953 (Ref: H);
Consolidated Waterworks of Rosario, comprising reports and accounts, 1897-1946, and notices and circulars, 1930-1955 (Ref: J);
Rosario Drainage Company, comprising reports and accounts, 1898-1947, and notices and circulars, 1955 (Ref: K);
Buenos Aires Central Railway, comprising minutes, 1916-1944 (Ref: L);
Buenos Aires and Lacroze Tramways, comprising minutes, 1932-1940, and reports and accounts, 1933-1941 (Ref: M).

Letters patent appointing the commissioners; orders of court; minutes of various Committees including the General Purposes Committee, By-laws Committee, Committee on Claims, Disposal of Refuse Committee, Finance Committee, Trial Works Committee, Sewage Manure Committee and Ordnance Survey Committee; original contracts for the construction of new sewers, including plans, sections and elevations; registers of in-letters; letter books for out-letters; drainage applications; registers of applications to construct sewers and drains; registers of proposed drainage of buildings; registers of house drainage; register of complaints; applications for private works on sewers and drains; registers of streets showing existence or absence of sewers and drains; surveyor's report books; staff records; financial accounts; rate books; printed items bound into volumes, including reports (several written by Joseph Bazalgette), papers, resolutions, prospectuses, surveys and inspections on various subjects including sewers and drains, cesspools, sewage, manure, waterways, flushing operations, public health, industrial sites, public conveniences, subterranean surveys, tides and water supply; minutes of the Commissioners and plans and maps of sewers, drains and waterways.

Papers of the Parkes family, 1634-1865. The main part of the collection consists of letters to Joseph Parkes. In addition, there are a few letters to his elder brother Josiah, to their father John, and to other members of the family. There are also a few miscellaneous papers. The Parkes family deeds are also part of the collection, consisting of family deeds, subsidiary title deeds, grants of mineral rights, deeds held as Trustees, and miscellaneous. The deeds are dated 1634-1800 and the correspondence is dated 1801-1865.

Records of the Lee Conservancy Catchment Board, including minutes of Board meetings; papers relating to staff including wages and superannuation; papers regarding the Sadler's Mill stream diversion; papers regarding flood relief and defences; correspondence and papers of the Association of River Authorities; papers relating to clearing the river; petitions; rainfall statistics; fishing rights; papers regarding members of the Board; drainage schemes; public relations files; papers regarding the Water Resources Act 1973; reports; papers regarding the acquisition of properties; and agreements for works, clearing, drainage, diversions, improvements, flood prevention, land sales and so on.