The legal context for State Switchblade Laws, for each state, it is :
I.Possession legal and carry legal :
1.Arizona Y Y
2.Florida Y Y
3.Iowa Y Y
4.Ohio Y Y
5.South Dakota Y Y
II .Possession legal and carry with restriction :
1.Alabama Y Y3
2.Arkansas Y Y2
3.Idaho Y Y3
4.Kentucky Y Y3
5.Maryland Y Y3
6.Nebraska Y Y3
7.NorthCarolina Y Y3
8.NorthDakota Y Y3
9.Oregon Y Y3
10.Utah Y Y3
11.Virginia Y Y3,4
12.West Virginia Y Y3,4
.III.Possession legal and not legal carry
1.California Y N
2.Georgia Y N
3.Minnesota Y1 N
4.Mississippi Y N
5.Missouri Y1 N
6.Montana Y1 N
7.Oklahoma Y N
8.Pennsylvania Y1 N
9.Rhode Island Y N
10.South Carolina Y N
11.Texas Y1 N
12.Wyoming Y N
IV. Possession not legal and not legal carry
1.Alaska N N
2.Colorado N N
3.Connecticut N N
4.Delaware N Y3,4
5.Hawaii N N
6.Illinois N N
7.Indiana N N
8.Kansas N N
9.Louisiana N N
10.Maine N N
11.Massachusetts N N
12.Michigan N N
13.Nevada N N
14.NewHampshire N N
15.NewJersey N N
16.NewMexico N N
17.NewYork N N
18.Tennessee N N
19.Vermont N N
20.Washington N N
21.Wisconsin N N
1Possession banned, but exception made for collectors and/orpossession as curios or antiques
2Carry allowed if blade is under 3.5 inches
3Carry allowed if not concealed
4Concealed Carry allowed with permit or license
Y = Yes
N = No
(The source is the November 1998 issue of Tactical Knives. This page was last updated on September 5, 2002
http://www.Rossnordeen.com)
So, possession legal for Switchblade it is a possibility in 29 US state.