The following print reference books are ones you can trust.
Almanac of American History. E 174.5 .A45 1983
Although basically a chronology, this work also has introductory essays by renowned historians. Divided into five major time spans in U.S. history from 986 to 1982, each section contains an essay followed by a chronology of events.
American Decades. E 169.12 .A419 1994 (Ref)
This multi-volume set documents and analyzes periods of contemporary American social history. Each volume begins with an overview and chronology covering the entire decade. Subject chapters follow, each including an explanatory background overview; subject-specific timeline; and alphabetically arranged entries discussing the people, events and ideas important to that subject during the period.
Chronicle of America. E174.5 .C55x 1995
Presented in a newspaper format with brief articles, this lavishly illustrated book presents a year-by-year account of the major events in American history and culture.
Encyclopedia of American Facts and Dates. E 174.5 .C3 1997
This is the only encyclopedia of American history that is arranged in both concurrent and chronological order. More than just a listing of dates, the entries are full of details about such things as business, entertainment, fashions, social issues, crime, science, architecture, philosophy, and religion.
Timetables of American History. E 174.5 .T55x
Arranged by the broad subjects of History and Politics, the Arts, Sciences and Technology, and Miscellaneous, the emphasis of this work is on placing events in U.S. history in a time frame alongside significant happenings in world history. Coverage extends to 1980.
While not necessarily the most scholarly, these timeline sites on the Web may help.