Websites of Museums with African Art collections

Michael C. Carlos Museum, Emory University
The museum’s collection of African art contains approximately 1,800 objects that reflect the size and diversity of the continent. Highlights include the Kom Beaded Bowl Figure from the Cameroon Grassfields, used by royalty to hold kola nuts for their guests; Mami Wata, the Ibibio water spirit from Southeast Nigeria; the Makonde Lipiko mask from northern Mozambique; and a Koranic writing tablet from Ethiopia.
http://collections.carlos.emory.edu/collections/2438/african-art

Fine Arts Museum of San Francisco -- de Young Museum
The de Young's African art collection features work from many areas of sub-Saharan Africa. You can search through it's collection online (unfortunately photos, as of this writing, are not very high resolution).
http://www.famsf.org/collections/african-art

National Museum of African Art, Smithsonian
Explore the museum's collections as well as its past exhibitions of "tradition-based" as well as contemporary arts. The site produces special web presentations for most of its exhibitions, and an archive of these is available online. In the collection area of the site you are able to search over 10,000 works in its database.
http://africa.si.edu

UCLA Fowler Museum of Cultural History
"One of the largest collections of African arts in the United States, the Fowler Museum’s holdings encompass metalwork, wood carvings, textiles, musical instruments, popular urban arts, and ceramics. These arts come from throughout the African continent and span millennia, reflecting the vibrancy and diversity of the arts from nearly every time period and region of the continent." Search the digital collection, and past exhibits.
http://fowler.ucla.edu/africa/

University of Pennsylvania Museum of Archaeology and Anthropology
"The African collection at the Penn Museum is one of the largest collections in the country. The collection includes approximately 15,000 ethnographic and 5,000 archaeological objects and most of the collection was obtained between 1891 and 1937. Although many of the artifacts can be appreciated from a purely artistic or aesthetic standpoint, the Museum's main interest in them is as an ethnographic study collection. The collection therefore contains everything from masks and statuary to architectural pieces, clothing, musical instruments and ordinary household implements."
http://www.penn.museum/about-collections/curatorial-sections/african-section

Royal Museum for Central Africa in Tervuren, Belgium
The Museum' permanent exhibits include its remarkable collection of ethnographic objects from Central Africa. The temporary exhibitions aim to be a podium for contemporary African art and science.
http://www.africamuseum.be/en

MFA Boston
"From shrine figures to palace pillars to historic men’s masks, the MFA’s department of African and Oceanic art includes important works from the 16th to 21st century that span two continents. Decorative arts, including clothing, headrests, staffs, and tableware, introduce visitors to the art of everyday life during the late 19th and early 20th centuries. Masks and artworks used in dance give a glimpse into the multimedia performance art tradition of masquerade." Search the image database for thousand of African items.
http://mfa.org/collections/africa-and-oceania

Brooklyn Museum, Arts of Africa Collection
"The Brooklyn Museum was one of the first museums in the United States to collect and exhibit the Arts of Africa. Our collection focuses primarily on historical works from Western, Central, Southern, and Eastern Africa, and includes contemporary art from across the continent. Numbering approximately 4,500 works, and spanning from 200 C.E. to today, the Arts of Africa collection is one of the most important of its kind in a U.S. art museum and covers millennia of African creativity."
http://www.brooklynmuseum.org/opencollection/collections/21

African Art Collection at The Met
"The Met's collection of art of the peoples of sub-Saharan Africa, the Pacific Islands, and North, Central, and South America comprises more than eleven thousand works of art of varied materials and types, representing diverse cultural traditions from as early as 3000 B.C.E. to the present. Highlights include decorative and ceremonial objects from the Court of Benin in Nigeria; sculpture from West and Central Africa."
http://www.metmuseum.org/art/collection/search?department=5&geolocation=Africa&showOnly=withImage

Arts of Global Africa, Minneapolis Institute of Art
"African and African Diaspora artists creating works of art, from Ancient Egypt to today. The collection includes masterworks of sculpture, ceramics, metalwork, and textiles, reflecting the diversity of African regions and cultures." You can browse thousand of objects online.
http://collections.artsmia.org/search/Arts%20of%20Global%20Africa

Arts of Africa, Dallas Museum of Art
"The DMA was an early advocate for the inclusion of African art in American art museums, and the Museum’s dedication to the field has set precedents since the 1950s. The collection is particularly strong in art from the Kongo and Luba cultures in Central Africa and the Yoruba and Edo (Benin kingdom) in West Africa." Over 2,000 objects online, easily searched by culture, date, artist, medium etc. High resolution downloads.
http://collections.dma.org/topic/departments/arts-of-africa

African Art at the British Museum
"Our African collection represents the rich and diverse history of a continent, from the beautiful bronze-casting of Igbo-Ukwu, Ife and Benin to objects that delve into the ritual of masquerade – traditional performances that express the secret knowledge of local communities." Take a virtual tour of the gallery, or search the British Museum's very large and extraordinary collection online.
http://www.britishmuseum.org/collection/africa

Detroit Institute of Art
Search the collection of African figures, masks, containers, carved stools, jewelry, and musical instruments.
http://dia.org

Online exhibitions

William Itter collection of African Pottery
An impressive collection of pottery from a long list of peoples from all over Africa. Nupe, Yoruba, Hausa, Mambila, Mangbetu, Bamileke, Lobi, Dagari, Bamana, Dogon, Makonde, Zulu, and more...
http://www.artistpotters.com/artist_exhibits/itter/index.htm

Digital Benin
"Digital Benin brings together all objects, historical photographs and rich documentation material from collections worldwide to provide a long-requested overview of the royal artefacts from Benin Kingdom looted in the late nineteenth century. The digital platform introduces new scholarship which connects digital documentation about the translocated objects to oral histories, object research, historical context, a foundational Edo language catalogue, provenance names, a map of the Benin Kingdom and museum collections worldwide. Digital Benin connects data from 5,246 objects across 131 institutions in 20 countries."
http://digitalbenin.org

Asafo Flags from the Karun Collection
An amazing collection of over 200 Asafo flags dating from as early as the 19th century. Along with an introductory essay by Duncan Clarke on the Asafo flags of the Fante people of western Ghana: "Appropriated from European naval ensigns and national flags, the form became the vessel for an exploration of local values and indigenous artistic creativity."
http://www.karuncollection.com/exhibitions-african-textiles-exhibition-at-the-brunei-gallery/

Imago Mundi collection
"Imago Mundi collection, a cultural, democratic, global, non-profit project, promoted by Luciano Benetton with the aim of creating the widest possible mapping of the different contemporary artistic experiences of our world. Each country is represented by the works of established and emerging artists, commissioned with the maximum freedom of expression, whose only constraint is the 10 x 12 cm format." Over 5,000 artists just from the African continent, you can view the artworks online, or purchase country catalogs.
http://imagomundicollection.org

In and Out of the Studio: Photographic Portraits from West Africa
The Metropolitan Museum's exhibit "presents one hundred years of portrait photography in West Africa through nearly eighty photographs taken between the 1870s and the 1970s. These photographers explored the possibilities of their medium, developing a rich aesthetic vocabulary through compelling self-portraits, staged images against painted backdrops or open landscapes, and casual snapshots of leisurely times. Photography allowed artists and patrons alike to express their articulation of what modernity looked like—one that was constantly reinvented." View all the photographs online.
http://www.metmuseum.org/exhibitions/listings/2015/in-and-out-of-the-studio