<s>
A	O
geo-fence	B-Application
warrant	I-Application
(	O
also	O
known	O
as	O
a	O
geofence	B-Application
warrant	I-Application
or	O
a	O
reverse	B-Application
location	I-Application
warrant	I-Application
)	O
is	O
a	O
search	O
warrant	O
issued	O
by	O
a	O
court	O
to	O
allow	O
law	O
enforcement	O
to	O
search	O
a	O
database	O
to	O
find	O
all	O
active	O
mobile	B-Application
devices	I-Application
within	O
a	O
particular	O
geo-fence	O
area	O
.	O
</s>
<s>
Courts	O
have	O
granted	O
law	O
enforcement	O
geo-fence	B-Application
warrants	I-Application
to	O
obtain	O
information	O
from	O
databases	O
such	O
as	O
Google	B-Application
's	I-Application
Sensorvault	B-Application
,	O
which	O
collects	O
users	O
 '	O
historical	O
geolocation	O
data	O
.	O
</s>
<s>
Geo-fence	B-Application
warrants	I-Application
are	O
a	O
part	O
of	O
a	O
category	O
of	O
warrants	O
known	O
as	O
reverse	O
search	O
warrants	O
.	O
</s>
<s>
Geo-fence	B-Application
warrants	I-Application
were	O
first	O
used	O
in	O
2016	O
.	O
</s>
<s>
Google	B-Application
reported	O
that	O
it	O
had	O
received	O
982	O
such	O
warrants	O
in	O
2018	O
,	O
8,396	O
in	O
2019	O
,	O
and	O
11,554	O
in	O
2020	O
.	O
</s>
<s>
A	O
2021	O
transparency	O
report	O
showed	O
that	O
25%	O
of	O
data	O
requests	O
from	O
law	O
enforcement	O
to	O
Google	B-Application
were	O
geo-fence	O
data	O
requests	O
.	O
</s>
<s>
Google	B-Application
is	O
the	O
most	O
common	O
recipient	O
of	O
geo-fence	B-Application
warrants	I-Application
and	O
the	O
main	O
provider	O
of	O
such	O
data	O
,	O
although	O
companies	O
including	O
Apple	O
,	O
Snapchat	B-Application
,	O
Lyft	B-Application
,	O
and	O
Uber	B-Application
have	O
also	O
received	O
such	O
warrants	O
.	O
</s>
<s>
Groups	O
including	O
the	O
Electronic	O
Frontier	O
Foundation	O
have	O
opposed	O
geofence	B-Application
warrants	I-Application
in	O
amicus	O
briefs	O
filed	O
in	O
motions	O
to	O
quash	O
such	O
orders	O
to	O
disclose	O
geofence	O
data	O
.	O
</s>
