From the United States Code, Title 36, Section 175:
US Code as of: 01/26/98
Sec. 175. Position and manner of display
The flag, when carried in a procession with another flag or flags, should
be either on the marching right; that is, the flag's own right, or, if there
is a line of other flags, in front of the center of that line.
(a) The flag should not be displayed on a float in a parade except from a
staff, or as provided in subsection (i) of this section.
(b) The flag should not be draped over the hood, top, sides, or back of a
vehicle or of a railroad train or a boat. When the flag is displayed on a
motorcar, the staff shall be fixed firmly to the chassis or clamped to the
right fender.
(c) No other flag or pennant should be placed above or, if on the same level,
to the right of the flag of the United States of America, except during church
services conducted by naval chaplains at sea, when the church pennant may
be flown above the flag during church services for the personnel of the Navy.
No person shall display the flag of the United Nations or any other national
or international flag equal, above, or in a position of superior prominence
or honor to, or in place of, the flag of the United States at any place within
the United States or any Territory or possession thereof: Provided, That nothing
in this section shall make unlawful the continuance of the practice heretofore
followed of displaying the flag of the United Nations in a position of superior
prominence or honor, and other national flags in positions of equal prominence
or honor, with that of the flag of the United States at the headquarters of
the United Nations.
(d) The flag of the United States of America, when it is displayed with another
flag against a wall from crossed staffs, should be on the right, the flag's
own right, and its staff should be in front of the staff of the other flag.
(e) The flag of the United States of America should be at the center and
at the highest point of the group when a number of flags of States or localities
or pennants of societies are grouped and displayed from staffs.
(f) When flags of States, cities, or localities, or pennants of societies
are flown on the same halyard with the flag of the United States, the latter
should always be at the peak. When the flags are flown from adjacent staffs,
the flag of the United States should be hoisted first and lowered last. No
such flag or pennant may be placed above the flag of the United States or
to the United States flag's right.
(g) When flags of two or more nations are displayed, they are to be flown
from separate staffs of the same height. The flags should be of approximately
equal size. International usage forbids the display of the flag of one nation
above that of another nation in time of peace.
(h) When the flag of the United States is displayed from a staff projecting
horizontally or at an angle from the window sill, balcony, or front of a building,
the union of the flag should be placed at the peak of the staff unless the
flag is at half staff. When the flag is suspended over a sidewalk from a rope
extending from a house to a pole at the edge of the sidewalk, the flag should
be hoisted out, union first, from the building.
(i) When displayed either horizontally or vertically against a wall, the
union should be uppermost and to the flag's own right, that is, to the observer's
left. When displayed in a window, the flag should be displayed in the same
way, with the union or blue field to the left of the observer in the street.
(j) When the flag is displayed over the middle of the street, it should be
suspended vertically with the union to the north in an east and west street
or to the east in a north and south street.
(k) When used on a speaker's platform, the flag, if displayed flat, should
be displayed above and behind the speaker. When displayed from a staff in
a church or public auditorium, the flag of the United States of America should
hold the position of superior prominence, in advance of the audience, and
in the position of honor at the clergyman's or speaker's right as he faces
the audience. Any other flag so displayed should be placed on the left of
the clergyman or speaker or to the right of the audience.
(l) The flag should form a distinctive feature of the ceremony of unveiling
a statue or monument, but it should never be used as the covering for the
statue or monument.
(m) The flag, when flown at half-staff, should be first hoisted to the peak
for an instant and then lowered to the half-staff position. The flag should
be again raised to the peak before it is lowered for the day. On Memorial
Day the flag should be displayed at half-staff until noon only, then raised
to the top of the staff. By order of the President, the flag shall be flown
at half-staff upon the death of principal figures of the United States Government
and the Governor of a State, territory, or possession, as a mark of respect
to their memory. In the event of the death of other officials or foreign dignitaries,
the flag is to be displayed at half-staff according to Presidential instructions
or orders, or in accordance with recognized customs or practices not inconsistent
with law. In the event of the death of a present or former official of the
government of any State, territory, or possession of the United States, the
Governor of that State, territory, or possession may proclaim that the National
flag shall be flown at half-staff. The flag shall be flown at half-staff thirty
days from the death of the President or a former President; ten days from
the day of death of the Vice President, the Chief Justice or a retired Chief
Justice of the United States, or the Speaker of the House of Representatives;
from the day of death until interment of an Associate Justice of the Supreme
Court, a Secretary of an executive or military department, a former Vice President,
or the Governor of a State, territory, or possession; and on the day of death
and the following day for a Member of Congress. The flag shall be flown at
halfstaff on Peace Officers Memorial Day, unless that day is also Armed Forces
Day. As used in this subsection -
(1) the term ''half-staff'' means the position of the flag when it is one-half
the distance between the top and bottom of the staff;
(2) the term ''executive or military department'' means any agency listed
under sections 101 and 102 of title 5; and
(3) the term ''Member of Congress'' means a Senator, a Representative, a Delegate,
or the Resident Commissioner from Puerto Rico.
(n) When the flag is used to cover a casket, it should be so placed that
the union is at the head and over the left shoulder. The flag should not be
lowered into the grave or allowed to touch the ground.
(o) When the flag is suspended across a corridor or lobby in a building with only one main entrance, it should be suspended vertically with the union of the flag to the observer's left upon entering. If the building has more than one main entrance, the flag should be suspended vertically near the center of the corridor or lobby with the union to the north, when entrances are to the east and west or to the east when entrances are to the north and south. If there are entrances in more than two directions, the union should be to the east.